Send a WebSocket close frame.
void close( close_reason const& cr, error_code& ec);
This function is used to synchronously send a close frame on the stream. The call blocks until one of the following is true:
This function is implemented in terms of one or more calls to the next
If the close reason specifies a close code other than beast::websocket::close_code::none, the close frame is sent with the close code and optional reason string. Otherwise, the close frame is sent with no payload.
Callers should not attempt to write WebSocket data after initiating the
close. Instead, callers should continue reading until an error occurs.
A read returning
websocket::closed indicates a successful
The reason for the close.
Set to indicate what error occurred, if any.