reserved value indicating that the connection was closed abnormally; must not be sent.
the endpoint received data that was invalid (eg, non-UTF-8 data in a text message).
the client/server is going away
the client is closing the connection because the server failed to negotiate a required extension.
reserved value indicating that no close code was present; must not be sent.
a normal, non-error close
generic error code indicating some sort of policy violation.
a protocol error occurred
the server is closing the connection because it was unable to fulfill the request.
reserved value indicating that the TLS handshake failed; must not be sent.
the endpoint received a message that is too big to process.
the endpoint received data of a type that it does not support.
Pre-defined close codes that can be passed to WebsocketConnection.close or received from WebsocketConnection.get_close_code.
However, other codes are also allowed.