Unsubscribes from measurements.
Subscriptions are ref-counted - multiple SubscribeMeasurements will require the same number of UnsubscribeMeasurements to unsubscribe.
The source to unsubscribe from, or WILDCARD for all assets.
string CHANNEL := "CumulocityIoT"Channel to send these events to.
string WILDCARD := "*"Wildcard value of assetId.
string assetIdThe source to unsubscribe from, or WILDCARD for all assets.