Clarify how Receivers must handle errors returned by Consume*() functions (#4267)
Clarify how Receivers must handle errors returned by Consume*() functions (#4267)

This is important to make sure failed Consume*() calls are correctly handled
by Receivers and that the Receives in turn correctly respond back to the senders
from which they received data.

We may need to audit all receivers to make sure they work according to these
requirements.
open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector