Exception for pausing the tasks due failed data retrieval

[creat89]

Hello,

As issues #338 and #312 describe, in occasions, the readers break due to external reasons, e.g. server down. This causes, currently that the task is completely stop because the readers launch an exception.

While the platform manages correctly exceptions in general, I wonder if there would be a way to trigger with certain exceptions a pause on the task and continue with other tasks that are waiting to be completed. Ideally, after some time, the task could be automatically unpaused or, in the worst case, unpaused by the user.