When Safari 13.1 for MacOS receives a compressed text message, it prints WebSocket connection to 'ws://localhost:8080/ws' failed: Could not decode a text frame as UTF-8 on the Javascript console and closes the WebSocket connection.

This is probably a bug in Safari. But this issue might help others to disable compression as a workaround. They have to pass AcceptOptions to Accept():

websocket.AcceptOptions{
	CompressionMode: websocket.CompressionDisabled,
}