Understanding a Channel Registered in netty 4, when can a channel be re-registered?

Question

As introduced in Netty New and notably in 4.0 :

channelOpen, channelBound and channelConnected are combined with channelActive. channelDisconnected, channelUnbound and channelClosed were merged into channelInactive. Similarly, Channel.isBound () and isConnected () were combined with isActive ().

Note that channelRegistered and channelUnregistered are not equivalent to channelOpen and channelClosed. These are new states introduced to support dynamic registration, deregistration and re-registration of the Channel, as shown below:

IMHO, in the TCP / IP scenario, when the channel is not registered, the corresponding socket is closed, how can it be re-registeragain?

Answer 1

, , NIO . , - . , , , (, OP_READ, OP_WRITE ..).