Sets a reason for rejecting the WebSocket handshake request.

@copydoc fwd_impl::request @pre `valid()`

Returns whether the connection state requires a shutdown of the socket connection.

@pre `ready == true`

Schedules a call to `do_handover` on the handler.

Sends the payload after the header.

Callback for the format string parser.

Sets a custom handler for error messages.

Sets a custom exception handler for this actor. If multiple handlers are defined, only the functor that was added *last* is being executed.

Sets a custom handler for node down messages.

Returns the number of elements in the list.

Combine UTF-16 high and low surrogates into a code point.

Sets the head to `new_head` and returns the previous head if the queue was not empty.

@relates observer_state