Motivation:
Some users already use an SSLEngine implementation in finagle-native. It
wraps OpenSSL to get higher SSL performance. However, to take advantage
of it, finagle-native must be compiled manually, and it means we cannot
pull it in as a dependency and thus we cannot test our SslHandler
against the OpenSSL-based SSLEngine. For an instance, we had #2216.
Because the construction procedures of JDK SSLEngine and OpenSslEngine
are very different from each other, we also need to provide a universal
way to enable SSL in a Netty application.
Modifications:
- Pull netty-tcnative in as an optional dependency.
http://netty.io/wiki/forked-tomcat-native.html
- Backport NativeLibraryLoader from 4.0
- Move OpenSSL-based SSLEngine implementation into our code base.
- Copied from finagle-native; originally written by @jpinner et al.
- Overall cleanup by @trustin.
- Run all SslHandler tests with both default SSLEngine and OpenSslEngine
- Add a unified API for creating an SSL context
- SslContext allows you to create a new SSLEngine or a new SslHandler
with your PKCS#8 key and X.509 certificate chain.
- Add JdkSslContext and its subclasses
- Add OpenSslServerContext
- Add ApplicationProtocolSelector to ensure the future support for NPN
(NextProtoNego) and ALPN (Application Layer Protocol Negotiation) on
the client-side.
- Add SimpleTrustManagerFactory to help a user write a
TrustManagerFactory easily, which should be useful for those who need
to write an alternative verification mechanism. For example, we can
use it to implement an unsafe TrustManagerFactory that accepts
self-signed certificates for testing purposes.
- Add InsecureTrustManagerFactory and FingerprintTrustManager for quick
and dirty testing
- Add SelfSignedCertificate class which generates a self-signed X.509
certificate very easily.
- Update all our examples to use SslContext.newClient/ServerContext()
- SslHandler now logs the chosen cipher suite when handshake is
finished.
Result:
- Cleaner unified API for configuring an SSL client and an SSL server
regardless of its internal implementation.
- When native libraries are available, OpenSSL-based SSLEngine
implementation is selected automatically to take advantage of its
performance benefit.
- Examples take advantage of this modification and thus are cleaner.
Motivation:
The old DefaultAttributeMap impl did more synchronization then needed and also did not expose a efficient way to check if an attribute exists with a specific key.
Modifications:
* Rewrite DefaultAttributeMap to not use IdentityHashMap and synchronization on the map directly. The new impl uses a combination of AtomicReferenceArray and synchronization per chain (linked-list). Also access the first Attribute per bucket can be done without any synchronization at all and just uses atomic operations. This should fit for most use-cases pretty weel.
* Add hasAttr(...) implementation
Result:
It's now possible to check for the existence of a attribute without create one. Synchronization is per linked-list and the first entry can even be added via atomic operation.
Motivation:
At the moment there are two issues with HashedWheelTimer:
* the memory footprint of it is pretty heavy (250kb fon an empty instance)
* the way how added Timeouts are handled is inefficient in terms of how locks etc are used and so a lot of context-switching / condition can happen.
Modification:
Rewrite HashedWheelTimer to use an optimized bucket implementation to store the submitted Timeouts and a MPSC queue to handover the timeouts. So volatile writes are reduced to a minimum and also the memory foot-print of the buckets itself is reduced a lot as the bucket uses a double-linked-list. Beside this we use Atomic*FieldUpdater where-ever possible to improve the memory foot-print and performance.
Result:
Lower memory-footprint and better performance
Motivation:
Some JDK versions of Mac OS X generates a JNI dynamic library with '.jnilib' extension rather than with '.dynlib' extension. However, System.mapLibraryName() always returns 'lib<name>.dynlib'. As a result, NativeLibraryLoader fails to load the native library whose extension is .jnilib.
Modification:
Try to find both '.jnilib' and '.dynlib' resources on OS X.
Result:
Dynamic libraries are loaded correctly in Mac OS X, and thus we can continue the OpenSslEngine work.
Motivation:
So far, we used a very simple platform string such as linux64 and
linux32. However, this is far from perfection because it does not
include anything about the CPU architecture.
Also, the current build tries to put multiple versions of .so files into
a single JAR. This doesn't work very well when we have to ship for many
different platforms. Think about shipping .so/.dynlib files for both
Linux and Mac OS X.
Modification:
- Use os-maven-plugin as an extension to determine the current OS and
CPU architecture reliable at build time
- Use Maven classifier instead of trying to put all shared libraries
into a single JAR
- NativeLibraryLoader does not guess the OS and bit mode anymore and it
always looks for the same location regardless of platform, because the
Maven classifier does the job instead.
Result:
Better scalable native library deployment and retrieval
Motivation:
It is less confusing not to spread Thread.interrupt() calls.
Modification:
- Comments
- Move generatorThread.interrupt() to where currentThread.interrupt() is
triggered
Result:
Code that is easier to read
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Remove ChannelHandlerInvoker.writeAndFlush(...) and the related
implementations.
Result:
4.1 and master got closer.
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Fix found differences
Result:
4.1 and master got closer.
Motivation:
ThreadLocalRandomTest reveals that ThreadLocalRandom's initial seed generation loop becomes tight if the thread is interrupted.
We currently interrupt ourselves inside the wait loop, which will raise an InterruptedException again in the next iteration, resulting in infinite (up to 3 seconds) exception construction and thread interruptions.
Modification:
- When the initial seed generator thread is interrupted, break out of the wait loop immediately.
- Log properly when the initial seed generation failed due to interruption.
- When failed to generate the initial seed, interrupt the generator thread just in case the SecureRandom implementation handles it properly.
- Make the initial seed generator thread daemon and handle potential exceptions raised due to the interruption.
Result:
No more tight loop on interruption. More robust generator thread termination. Fixes#2412
Motivation:
When using System.getProperty(...) and various methods to get a ClassLoader it will fail when a SecurityManager is in place.
Modifications:
Use a priveled block if needed. This work is based in the PR #2353 done by @anilsaldhana .
Result:
Code works also when SecurityManager is present
Motivation:
EventExecutor.iterator() is fixed to return Iterator<EventExecutor> and there's no way to change that as long as we don't extend Iterable. However, a user should have a way to cast the returned set of executors painlessly. Currently, it is only possible with an explicit cast like (Iterator<NioEventLoop>).
Modifications:
Instead, I added a new method called 'children()' which returns an immutable collection of child executors whose method signature looks like the following:
<E extends EventExecutor> Set<E> children();
Result:
A user can now do this:
Set<NioEventLoop> loops = group.children();
for (NioEventLoop l: loops) { ... }
Unfortunately, this is not possible:
for (NioEventLoop l: group.children()) { ... }
However, it's still a gain that a user doesn't need to down-cast explicitly and to add the '@SuppressWarnings` annotation.
Motivation:
There's no reason to keep our users from using DefaultEventExecutor directly. It should be actually very useful to them.
Modifications:
Make DefaultEventExecutor public and add useful public constructors.
Result:
DefaultEventExecutor got usable by anyone, yielding more value as a generic library.
Motivation:
AbstractEventExecutor and AbstractEventExecutorGroup have hard-coded magic timeout numbers. They should have the same timeout numbers, but it's easy to break that rule because they are hard-coded in each place.
Modifications:
Add package private constants to AbstractEventExecutor and let AbstractEventExecutorGroup use them.
Result:
Single timeout change affects two classes.
Motivation:
EventExecutor.parent() and EventLoop.parent() almost always return a constant parent executor. There's not much reason to let it implemented in subclasses.
Modifications:
- Implement AbstractEventExecutor.parent() with an additional contructor
- Add AbstractEventLoop so that subclasses extend AbstractEventLoop, which implements parent() appropriately
- Remove redundant parent() implementations in the subclasses
- Fix inspector warnings
Result:
Less duplication.
Motivation:
Previously, we used SecureRandom.nextLong() to generate the initialSeedUniquifier. This required more entrophy than necessary because it has to 1) generate the seed of SecureRandom first and then 2) generate a random long integer. Instead, we can use generateSeed() to skip the step (2)
Modifications:
Use generateSeed() instead of nextLong()
Result:
ThreadLocalRandom requires less amount of entrphy to start up
Motivation:
As reported in #2331, some query operations in NetworkInterface takes much longer time than we expected. For example, specifying -Djava.net.preferIPv4Stack=true option in Window increases the execution time by more than 4 times. Some Windows systems have more than 20 network interfaces, and this problem gets bigger as the number of unused (virtual) NICs increases.
Modification:
Use NetworkInterface.getInetAddresses() wherever possible.
Before iterating over all NICs reported by NetworkInterface, filter the NICs without proper InetAddresses. This reduces the number of candidates quite a lot.
NetUtil does not query hardware address of NIC in the first place but uses InetAddress.isLoopbackAddress().
Do not call unnecessary query operations on NetworkInterface. Just get hardware address and compare.
Result:
Significantly reduced class initialization time, which should fix#2331.
Motivation:
6e8ba291cf introduced a regression in Android because Android does not have sun.nio.ch.DirectBuffer (see #2330.) I also found PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() are pretty much same after the commit and the unsafe version should be removed.
Modifications:
- Do not use the pooled allocator in Android because it's too resource hungry for Androids.
- Merge PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() into one method.
- Make the Unsafe unavailable when sun.nio.ch.DirectBuffer is unavailable. We could keep the Unsafe available and handle the sun.nio.ch.DirectBuffer case separately, but I don't want to complicate our code just because of that. All supported JDK versions have sun.nio.ch.DirectBuffer if the Unsafe is available.
Result:
Simpler code. Fixes Android support (#2330)
Motivation:
'io.netty.recycler.maxCapacity.default' is the only property for recycler's default maximum capacity, so having the 'default' suffix only increases the length of the property name.
Modifications:
Rename "io.netty.recycler.maxCapacity.default" to "io.netty.recycler.maxCapacity"
Result:
Shorter system property name. The future addition of system properties, such as io.netty.recycler.maxCapacity.outboundBuffer, are not confusing either.
Motivation:
Remove the synchronization bottleneck in startThread() which is called by each execute(..) call from outside the EventLoop.
Modifications:
Replace the synchronized block with the use of AtomicInteger and compareAndSet loops.
Result:
Less conditions during SingleThreadEventExecutor.execute(...)
Motivation:
- As reported recently [1], Recycler's thread-local object pool has unbounded capacity which is a potential problem.
- It accesses a hash table on each push and pop for debugging purposes. We don't really need it besides debugging Netty itself.
Modifications:
- Introduced the maxCapacity constructor parameter to Recycler. The default default maxCapacity is retrieved from the system property whose default is 256K, which should be plenty for most cases.
- Recycler.Stack.map is now created and accessed only when assertion is enabled for Recycler.
Result:
- Recycler does not grow infinitely anymore.
- If assertion is disabled, Recycler should be much faster.
[1] https://github.com/netty/netty/issues/1841
Previously ConcurrentHashMapV8 evaulated ((x | 1) == 0), an expression
that always returned false. This commit brings Netty closer to the
Java 8 implementation.
This transport use JNI (C) to directly make use of epoll in Edge-Triggered mode for maximal performance on Linux. Beside this it also support using TCP_CORK and produce less GC then the NIO transport using JDK NIO.
It only builds on linux and skip the build if linux is not used. The transport produce a jar which contains all needed .so files for 32bit and 64 bit. The user only need to include the jar as dependency as usually
to make use of it and use the correct classes.
This includes also some cleanup of @trustin
- Related: #2163
- Add ResourceLeakHint to allow a user to provide a meaningful information about the leak when touching it
- DefaultChannelHandlerContext now implements ResourceLeakHint to tell where the message is going.
- Cleaner resource leak report by excluding noisy stack trace elements
- Proposed fix for #1824
UniqueName and its subtypes do not allow getting the previously registered instance. For example, let's assume that a user is running his/her application in an OSGi container with Netty bundles and his server bundle. Whenever the server bundle is reloaded, the server will try to create a new AttributeKey instance with the same name. However, Netty bundles were not reloaded at all, so AttributeKey will complain that the name is taken already (by the previously loaded bundle.)
To fix this problem:
- Replaced UniqueName with Constant, AbstractConstant, and ConstantPool. Better name and better design.
- Sctp/Udt/RxtxChannelOption is not a ChannelOption anymore. They are just constant providers and ChannelOption is final now. It's because caching anything that's from outside of netty-transport will lead to ClassCastException on reload, because ChannelOption's constant pool will keep all option objects for reuse.
- Signal implements Constant because we can't ensure its uniqueness anymore by relying on the exception raised by UniqueName's constructor.
- Fixes#2220
- Its Javadoc says it returns true when the promise is done (but not cancelled) or the promise is uncancellable, but it returns false when the promise is done.
.. which occurs when a user adds a listener from different threads after the promise is done and the notifications for the listeners, that were added before the promise is done, is in progress. For instance:
Thread-1: p.addListener(listenerA);
Thread-1: p.setSuccess(null);
Thread-2: p.addListener(listenerB);
Thread-2: p.executor.execute(taskNotifyListenerB);
Thread-1: p.executor.execute(taskNotifyListenerA);
taskNotifyListenerB should not really notify listenerB until taskNotifyListenerA is finished.
To fix this issue:
- Change the semantic of (listeners == null) to determine if the early
listeners [1] were notified
- If a late listener is added before the early listeners are notified,
the notification of the late listener is deferred until the early
listeners are notified (i.e. until listeners == null)
- The late listeners with deferred notifications are stored in a lazily
instantiated queue to preserve ordering, and then are notified once
the early listeners are notified.
[1] the listeners that were added before the promise is done
[2] the listeners that were added after the promise is done
- Remove the reference to ResourceLeak from the buffer implementations
and use wrappers instead:
- SimpleLeakAwareByteBuf and AdvancedLeakAwareByteBuf
- It is now allocator's responsibility to create a leak-aware buffer.
- Added AbstractByteBufAllocator.toLeakAwareBuffer() for easier
implementation
- Add WrappedByteBuf to reduce duplication between *LeakAwareByteBuf and
UnreleasableByteBuf
- Raise the level of leak reports to ERROR - because it will break the
app eventually
- Replace enabled/disabled property with the leak detection level
- Only print stack trace when level is ADVANCED or above to avoid user
confusion
- Add the 'leak' build profile, which enables highly detailed leak
reporting during the build
- Remove ResourceLeakException which is unsed anymore
- Fixes#2003 properly
- Instead of using 'bundle' packaging, use 'jar' packaging. This is
more robust because some strict build tools fail to retrieve the
artifacts from a Maven repository unless their packaging is not 'jar'.
- All artifacts now contain META-INF/io.netty.version.properties, which
provides the detailed information about the build and repository.
- Removed OSGi testsuite temporarily because it gives false errors
during split package test and examination.
- Add io.netty.util.Version for easy retrieval of version information
- Fixes#1765
Java 6 did a poor job of generating seedUniquifier unlike 7, so I implemented platform-independent seedUniquifier generator with configurability
The problem was that with OioSocketChannel there was always a read Task in the taskQueue and with the old logic it never tried to execute scheduled tasks if there was at least one task in the taskQueue.
- Fix a bug in DefaultProgressivePromise.tryProgress() where the notification is dropped
- Fix a bug in AbstractChannel.calculateMessageSize() where FileRegion is not counted
- HttpStaticFileServer example now uses zero copy file transfer if possible.
- Fixes#1445
- Add PlatformDependent.maxDirectMemory()
- Ensure the default number or arenas is decreased if the max memory of the VM is not large enough.
- Related issue: #1432
- Add Future.isCancellable()
- Add Promise.setUncancellable() which is meant to be used for the party that runs the task uncancellable once started
- Implement Future.isCancelled() and Promise.cancel(boolean) properly
The API changes made so far turned out to increase the memory footprint
and consumption while our intention was actually decreasing them.
Memory consumption issue:
When there are many connections which does not exchange data frequently,
the old Netty 4 API spent a lot more memory than 3 because it always
allocates per-handler buffer for each connection unless otherwise
explicitly stated by a user. In a usual real world load, a client
doesn't always send requests without pausing, so the idea of having a
buffer whose life cycle if bound to the life cycle of a connection
didn't work as expected.
Memory footprint issue:
The old Netty 4 API decreased overall memory footprint by a great deal
in many cases. It was mainly because the old Netty 4 API did not
allocate a new buffer and event object for each read. Instead, it
created a new buffer for each handler in a pipeline. This works pretty
well as long as the number of handlers in a pipeline is only a few.
However, for a highly modular application with many handlers which
handles connections which lasts for relatively short period, it actually
makes the memory footprint issue much worse.
Changes:
All in all, this is about retaining all the good changes we made in 4 so
far such as better thread model and going back to the way how we dealt
with message events in 3.
To fix the memory consumption/footprint issue mentioned above, we made a
hard decision to break the backward compatibility again with the
following changes:
- Remove MessageBuf
- Merge Buf into ByteBuf
- Merge ChannelInboundByte/MessageHandler and ChannelStateHandler into ChannelInboundHandler
- Similar changes were made to the adapter classes
- Merge ChannelOutboundByte/MessageHandler and ChannelOperationHandler into ChannelOutboundHandler
- Similar changes were made to the adapter classes
- Introduce MessageList which is similar to `MessageEvent` in Netty 3
- Replace inboundBufferUpdated(ctx) with messageReceived(ctx, MessageList)
- Replace flush(ctx, promise) with write(ctx, MessageList, promise)
- Remove ByteToByteEncoder/Decoder/Codec
- Replaced by MessageToByteEncoder<ByteBuf>, ByteToMessageDecoder<ByteBuf>, and ByteMessageCodec<ByteBuf>
- Merge EmbeddedByteChannel and EmbeddedMessageChannel into EmbeddedChannel
- Add SimpleChannelInboundHandler which is sometimes more useful than
ChannelInboundHandlerAdapter
- Bring back Channel.isWritable() from Netty 3
- Add ChannelInboundHandler.channelWritabilityChanges() event
- Add RecvByteBufAllocator configuration property
- Similar to ReceiveBufferSizePredictor in Netty 3
- Some existing configuration properties such as
DatagramChannelConfig.receivePacketSize is gone now.
- Remove suspend/resumeIntermediaryDeallocation() in ByteBuf
This change would have been impossible without @normanmaurer's help. He
fixed, ported, and improved many parts of the changes.
- Fixes#1282 (not perfectly, but to the extent it's possible with the current API)
- Add AddressedEnvelope and DefaultAddressedEnvelope
- Make DatagramPacket extend DefaultAddressedEnvelope<ByteBuf, InetSocketAddress>
- Rename ByteBufHolder.data() to content() so that a message can implement both AddressedEnvelope and ByteBufHolder (DatagramPacket does) without introducing two getter methods for the content
- Datagram channel implementations now understand ByteBuf and ByteBufHolder as a message with unspecified remote address.
shutdownGracefully() provides two optional parameters that give more
control over when an executor has to be shut down.
- Related issue: #1307
- Add shutdownGracefully(..) and isShuttingDown()
- Deprecate shutdown() / shutdownNow()
- Replace lastAccessTime with lastExecutionTime and update it after task
execution for accurate quiet period check
- runAllTasks() and runShutdownTasks() update it automatically.
- Add updateLastExecutionTime() so that subclasses can update it
- Add a constructor parameter that tells not to add an unncessary wakeup
task in execute() if addTask() wakes up the executor thread
automatically. Previously, execute() always called wakeup() after
addTask(), which often caused an extra dummy task in the task queue.
- Use shutdownGracefully() wherever possible / Deprecation javadoc
- Reduce the running time of SingleThreadEventLoopTest from 40s to 15s
using custom graceful shutdown parameters
- Other changes made along with this commit:
- takeTask() does not throw InterruptedException anymore.
- Returns null on interruption or wakeup
- Make sure runShutdownTasks() return true even if an exception was
raised while running the shutdown tasks
- Remove unnecessary isShutdown() checks
- Consistent use of SingleThreadEventExecutor.nanoTime()
Replace isWakeupOverridden with a constructor parameter
- Do not attempt to validate localhost by binding a socket because it can fail when SecurityManager is in use
- Find loopback interface first and get address from there instead of getting loopback address from InetAddress.getLocalHost() (because it's more reliable)
- Instead of throwing an Error, just log and fall back to 127.0.0.1 while determining localhost address
- Now works without the transport package
- Renamed TransferFuture to ProgressiveFuture and ChannelProgressiveFuture / same for promises
- ProgressiveFutureListener now extends GenericProgressiveFutureListener and GenericFutureListener (add/removeTransferListener*() were removed)
- Renamed DefaultEventListeners to DefaultFutureListeners and only accept GenericFutureListeners
- Various clean-up
- Count the number of select() calls made to wait until reaching at the expected dead line, and rebuild selectors if too many select() calls were made.
- Rename directbyDefault to preferDirect
- Add a system property 'io.netty.prederDirect' to allow a user from changing the preference on launch-time
- Merge UnpooledByteBufAllocator.DEFAULT_BY_* to DEFAULT
- Borrow SLF4J API which is the best of the best
- InternalLoggerFactory now automatically detects the logging framework
using static class loading. It tries SLF4J, Log4J, and then falls back
to java.util.logging.
- Remove OsgiLogger because it is very likely that OSGi container
already provides a bridge for existing logging frameworks
- Remove JBossLogger because the latest JBossLogger implementation seems
to implement SLF4J binding
- Upgrade SLF4J to 1.7.2
- Remove tests for the untestable logging frameworks
- Remove TestAny
Now that we are going to use buffer pooling by default, it is obvious
that a user will forget to call .free() and report memory leak. In this
case, we should have a tool to determine if it is a bug in our allocator
implementation or in the user's code.
This pull request adds a system property flag called
'io.netty.resourceLeakDetection'. If set, when a user forgets to call
.free(), the ResourceLeakDetector will detect it and log a message with
detailed stack trace to tell where the leaked buffer has been allocated.
Because obtaining stack trace is an expensive operation, I used sampling
technique. Allocation is recorded only for every 113th allocation. I
chose 113 because it's a prime number.
In production, a user might not want to enable this option due to
potential performance impact. If a user does not specify the
'-Dio.netty.resourceLeakDetection' option leak detection is disabled.
Even if the leak detection is enabled, the overhead should be less than
5% because only ~1% of allocations are monitored.
I also replaced SharedResourceMisuseDetector with ResourceLeakDetector.
- Add PooledUnsafeDirectByteBuf, a variant of PooledDirectByteBuf, which
accesses its underlying direct ByteBuffer using sun.misc.Unsafe.
- To decouple Netty from sun.misc.*, sun.misc.Unsafe is accessed via
PlatformDependent.
- This change solely introduces about 8+% improvement in direct memory
access according to the tests conducted as described in #918
use single static initialization of available metrics monitor registries
* This changes the original implementation to work in a similar way to
how slf4j selects and loads an implementation.
* Uses a single static instance so intialization is done only once.
* Doesn't throw IllegalStateException if multiple implementations are
found on the classpath. It instead selects and uses the first
implementation returned by iterator()
* Class left as an iterable to keep the API the same
add yammer metrics to examples to allow them to publish metrics
publish the number of threads used in an EventLoopGroup see issue #718
* seems like the better place to put this because it sets the default
thread count if the MultithreadEventLoopGroup uses super(0,...)
* It also happens to be the common parent class amongst all the
MultiThreadedEventLoopGroup implementations
* Count is reported for
io.netty.channel.{*,.local,.socket.aio,.socket.nio}
fix cosmetic issues pointed out in pull request and updated notice.txt
see https://github.com/netty/netty/pull/780
count # of channels registered in single threaded event loop
measure how many times Selector.select return before SELECT_TIME
This commit introduces a new API for ByteBuf allocation which fixes
issue #643 along with refactoring of ByteBuf for simplicity and better
performance. (see #62)
A user can configure the ByteBufAllocator of a Channel via
ChannelOption.ALLOCATOR or ChannelConfig.get/setAllocator(). The
default allocator is currently UnpooledByteBufAllocator.HEAP_BY_DEFAULT.
To allocate a buffer, do not use Unpooled anymore. do the following:
ctx.alloc().buffer(...); // allocator chooses the buffer type.
ctx.alloc().heapBuffer(...);
ctx.alloc().directBuffer(...);
To deallocate a buffer, use the unsafe free() operation:
((UnsafeByteBuf) buf).free();
The following is the list of the relevant changes:
- Add ChannelInboundHandler.freeInboundBuffer() and
ChannelOutboundHandler.freeOutboundBuffer() to let a user free the
buffer he or she allocated. ChannelHandler adapter classes implement
is already, so most users won't need to call free() by themselves.
freeIn/OutboundBuffer() methods are invoked when a Channel is closed
and deregistered.
- All ByteBuf by contract must implement UnsafeByteBuf. To access an
unsafe operation: ((UnsafeByteBuf) buf).internalNioBuffer()
- Replace WrappedByteBuf and ByteBuf.Unsafe with UnsafeByteBuf to
simplify overall class hierarchy and to avoid unnecesary instantiation
of Unsafe instances on an unsafe operation.
- Remove buffer reference counting which is confusing
- Instantiate SwappedByteBuf lazily to avoid instantiation cost
- Rename ChannelFutureFactory to ChannelPropertyAccess and move common
methods between Channel and ChannelHandlerContext there. Also made it
package-private to hide it from a user.
- Remove unused unsafe operations such as newBuffer()
- Add DetectionUtil.canFreeDirectBuffer() so that an allocator decides
which buffer type to use safely
