- AbstractChannel keeps the expected number of written bytes so that
the ChannelFuture of a flush() operation is notified on right timing.
- Added ChannelBufferHolder.size() to make this possible
- Added AbstractChannel.isCompatible() so that only compatible EventLoop
is accepted by a channel on registration
- Added ChannelOption to make channel options type-safe
- Moved writeSpinCount property to ChannelConfig and removed Nio*Config
- Miscellaneous cleanup
introducing
ChannelOption