x.websocket: add header to client (#9517)

vlib/x/websocket/handshake.v

@@ -22,7 +22,12 @@ fn (mut ws Client) handshake() ? {
 	sb.write_string('\r\nUpgrade: websocket\r\nConnection: Upgrade\r\n')
 	sb.write_string('Sec-WebSocket-Key: ')
 	sb.write_string(seckey)
-	sb.write_string('\r\nSec-WebSocket-Version: 13\r\n\r\n')
+	sb.write_string('\r\nSec-WebSocket-Version: 13')
+	for key in ws.header.keys() {
+		val := ws.header.values_str(key).join(',')
+		sb.write_string('\r\n$key:$val')
+	}
+	sb.write_string('\r\n\r\n')
 	handshake := sb.str()
 	defer {
 		unsafe { handshake.free() }

vlib/x/websocket/websocket_client.v

@@ -4,6 +4,7 @@
 module websocket
 
 import net
+import net.http
 import x.openssl
 import net.urllib
 import time
@@ -30,6 +31,7 @@ pub:
 	uri    Uri    // uri of current connection
 	id     string // unique id of client
 pub mut:
+	header            http.Header  // headers that will be passed when connecting
 	conn              &net.TcpConn // underlying TCP socket connection
 	nonce_size        int = 16 // size of nounce used for masking
 	panic_on_callback bool     // set to true of callbacks can panic
@@ -85,6 +87,7 @@ pub fn new_client(address string) ?&Client {
 		uri: uri
 		state: .closed
 		id: rand.uuid_v4()
+		header: http.new_header()
 	}
 }
 
@@ -486,5 +489,6 @@ pub fn (c &Client) free() {
 		c.error_callbacks.free()
 		c.open_callbacks.free()
 		c.close_callbacks.free()
+		c.header.free()
 	}
 }