Motiviation:
There are currently no accessors which provide visbility into how many bytes must be written in order for a writability change to occur. This feature would be useful for codecs which intent to control how many bytes are queued at any given time.
Modifications:
- add bytesBeforeUnWritable() which will give the number of bytes before the buffer (and associated channel) transitions to not writable
- add bytesBeforeWritable() which will give the number of bytes that must be drained from the queue until the channel becomes writable.
Result:
More visibility into writability for the ChannelOutboundBuffer.