How to differentiate connecting and connected states?

[nailgilaziev]

First snapshot that StreamBuilder receives is ConnectionState.waiting
This happens when connecting started and in progress.

after connection is established we do not receive any new snapshots. This is undetermined state.
used this code https://flutter.io/cookbook/networking/web-sockets/
print lines added to track snapshots

new StreamBuilder(
  stream: widget.channel.stream,
  builder: (context, snapshot) {
    print("connection state ${snapshot.connectionState}");
    print("data ${snapshot.data}");
    print("error ${snapshot.error}");
    return new Padding(
      padding: const EdgeInsets.symmetric(vertical: 24.0),
      child: new Text(snapshot.hasData ? '${snapshot.data}' : ''),
    );
  },

in logs you see only

I/flutter ( 7150): connection state ConnectionState.waiting
I/flutter ( 7150): data null
I/flutter ( 7150): error null

If connection successful - last snapshot is ConnectionState.waiting
If connection not successful and will die in future (ConnectionTimeout around 2 min) - now you see ConnectionState.waiting and can't decide what to do.

snapshot will be active only when server sends some data to client.

[nailgilaziev]

detailed info about connectionTimeOut in https://github.com/dart-lang/web_socket_channel/issues/22

[nex3]

The StreamBuilder and ConnectionState classes are both from Flutter; I'm moving this issue to their repo.

[nex3]

This issue was moved to flutter/flutter#18204