3.1.2.5.3 Connection Close or Connection Error Encountered
Connection close and connection error MUST be handled identically. This section discusses connection close only.
A connection close can be initiated by either the client or the server. If a connection close is initiated by the client, the mixed proxy MUST close the connection to the server and transition to the closed state. If a connection close is initiated by the server, the mixed proxy MUST close the connection to the client and transition to the closed state.