mongoose/docs/c-api/mg_http.h/mg_send_websocket_handshake3.md

title	decl_name	symbol_kind	signature
mg_send_websocket_handshake3()	mg_send_websocket_handshake3	func	void mg_send_websocket_handshake3(struct mg_connection *nc, const char *path, const char *host, const char *protocol, const char *extra_headers, const char *user, const char *pass);

Like mg_send_websocket_handshake2 but also passes basic auth header