d6f0d12a86
Related issue: #2717, #2710, #2704, #2693 Motivation: When ChannelOutboundBuffer.nioBuffers() iterates over the linked list of entries, it is not supposed to visit unflushed entries, but it does. Modifications: - Make sure ChannelOutboundBuffer.nioBuffers() stops the iteration before it visits an unflushed entry - Add isFlushedEntry() to reduce the chance of the similar mistakes Result: Another regression is gone.