RAFT log message clarification: Aborting deliver for request because of background error

This is a request for log message clarification, not a bug. We see a very general log message as below:

2019-02-26 21:23:18.013 UTC [common.deliver] deliverBlocks -> WARN 50b16 Aborting deliver for request because of background error
2019-02-26 21:23:18.023 UTC [common.deliver] deliverBlocks -> WARN 50b83 Aborting deliver for request because of background error
2019-02-26 21:23:18.040 UTC [common.deliver] deliverBlocks -> WARN 50bc8 Aborting deliver for request because of background error
2019-02-26 21:23:18.040 UTC [common.deliver] deliverBlocks -> WARN 50bc9 Aborting deliver for request because of background error
2019-02-26 21:23:18.040 UTC [common.deliver] deliverBlocks -> WARN 50bca Aborting deliver for request because of background error
2019-02-26 21:23:18.042 UTC [common.deliver] deliverBlocks -> WARN 50be8 Aborting deliver for request because of background error
2019-02-26 21:23:18.062 UTC [common.deliver] deliverBlocks -> WARN 50c2a Aborting deliver for request because of background error

Yacov answered in the slack channel: the background error is just because you received something in the `errorChan`

Please add more information in the log message to help users to understand this.