Issue 688: FEC estimates block duration

[baranovmv]

Reader and writer esimate duration of FEC block in ns as this value could vary even though number of packets is known. For now it is decided to keep the greates value seen in the current session, not average.

#688

[github-actions[bot]]

:robot: Upon creation, pull request description does not have a link to an issue. If there is a related issue, please add it to the description using any of the supported formats.

[github-actions[bot]]

:robot: The latest upstream change made this pull request unmergeable. Please resolve the merge conflicts.

[gavv]

Thanks!!

Follow-up: 5fedaf4b14ecfba1011ea44ca9c14b53c8993467