NOTE
Netty Bind Source: Registering the Channel
Assigning a Channel to an EventLoop, registering with selector/transport state, and firing registration events.
This is a historical learning note and may contain outdated or incomplete understanding.
Registration assigns the channel to an EventLoop and performs the transport-specific registration required for readiness/event processing. If registration is requested from another thread, work is scheduled onto the event-loop thread to preserve confinement.
After successful registration, pipeline lifecycle events reflect the registered/active state as appropriate.
Selector keys, interest ops, unsafe/internal methods, and exact event order should be read against the specific Netty version. The stable rule is that registered channel I/O is owned by its event loop.