support catching exception on last try.

[cailiang9]

In many tasks that process a queue, e.g., when the source data is missing, the call func(item) will never be able to get job done. But we can simply ignore and continue on other items. So we need an option to not re-raise exception of the last try .

[umrashrf]

👍

[andrew-synapse]

@cailiang9 you can also return if current retry is last one. This will allow you to resume the execution call.