View Source ExTDLib.Object.MessageProximityAlertTriggered (ExTDLib v0.0.4)

A user in the chat came within proximity alert range.

NameTypeDescription
traveler_idMessageSenderThe identifier of a user or chat that triggered the proximity alert.
watcher_idMessageSenderThe identifier of a user or chat that subscribed for the proximity alert.
distancenumberThe distance between the users.

More details on telegram's documentation.