If ABORT is used as return value, the sender should close the channel all
the way to the upstream source. The ABORT will not guarantee that no
more events are delivered since this is impossible in a concurrent
environment. The consumer should accept subsequent events and close/clean
up when the Close or Error event is received.
Though ABORT has the value -1, any value less than 0 will act as an
A 0 indicates that the consumer is willing to receive subsequent events
at full speeds.
Any value more than 0 will indicate that the consumer is becoming
overloaded and wants a delay of the given milliseconds before the next
event is sent. This allows the consumer to pushback the event delivery