Added Break implementation for windows

serial_windows.go

@@ -382,7 +382,17 @@ func (port *windowsPort) SetReadTimeout(timeout time.Duration) error {
 }
 
 func (port *windowsPort) Break(d time.Duration) error {
-	return &PortError{code: FunctionNotImplemented}
+	if err := setCommBreak(port.handle); err != nil {
+		return &PortError{causedBy: err}
+	}
+
+	time.Sleep(d)
+
+	if err := clearCommBreak(port.handle); err != nil {
+		return &PortError{causedBy: err}
+	}
+
+	return nil
 }
 
 func createOverlappedEvent() (*syscall.Overlapped, error) {