setState not working inside firestore onsnapshot

Question

I am not getting any way to setState inside firestore onsnapshot method. please help me to find my mistake:

firestore()
      .collection('Chats')
      .where('trip_id', '==', this.props.route.params.tripId)
      .onSnapshot(snapshot => {
        var chats = [];
        snapshot.forEach(async e => {
          chats.push({
            sent_by: e.data().sender_id,
            message: e.data().message,
          });
        });
        console.log(chats); /// working here
        this.setState({
          chatmessage: chats, /// not working
          chatwindow: true,
        });
      });

    console.log(this.state.chatmessage); /// not working