pubsub: clarify doc for ReceiveSettings.NumGoroutines
Fixes
@@ -152,6 +152,12 @@ type ReceiveSettings struct {
// NumGoroutines is the number of goroutines Receive will spawn to pull
// messages concurrently. If NumGoroutines is less than 1, it will be treated
// as if it were DefaultReceiveSettings.NumGoroutines.
+ //
+ // NumGoroutines does not limit the number of messages that can be processed
+ // concurrently. Even with one goroutine, many messages might be processed at
+ // once, because that goroutine may continually receive messages and invoke the
+ // function passed to Receive on them. To limit the number of messages being
+ // processed concurrently, set MaxOutstandingMessages.
NumGoroutines int
}
