{
"type": "im_created",
"user": "U024BE7LH",
"channel": {...}
}
The im_created event is sent to all connections for a user when a new
direct message channel is created that they are a member of.
This message lets the client know that a channel has been created, but the
client should show no changes based on this, just update its internal list of
IM channels. Usually this event is followed by an
im_open event.