NOTE
Netty Pipeline: Outbound Events
Propagation of writes, flushes, binds, connects, closes, and other outbound operations through handlers toward the transport.
This is a historical learning note and may contain outdated or incomplete understanding.
Outbound operations originate from application/pipeline actions such as write, flush, connect, bind, close, and related calls, then travel through matching outbound contexts toward the channel transport.
A handler can transform, buffer, reject, or forward the operation. Completion is represented by promises/futures, so failures should complete those signals rather than disappear.
write and flush are distinct concepts: writes may accumulate until flushed according to pipeline/transport behavior.