ConnectionMonitor

This method is called after the connection's underlying socket has been closed. E.g., due to the close() request of the user, if the peer closed the connection, due to a fatal error during connect() (also if the socket cannot be established) or if a fatal error occured on an established connection.

This is an experimental feature.

You MUST NOT make any assumption about the thread that invokes this method.

Please note: if the connection is not connected (e.g., there was no successful connect() call), then the invocation of close() will NOT trigger this method.