Hardcoded timeout parameters in parallel read/write code

[JustinKyleJames]

In the parallel read/write cases, there are a couple of timeout parameters.

1. Twice waiting for a condition variable for the # of outstanding callbacks. One is waiting for the #outstanding to be 0. The other is waiting for it to be less than optimal_count. (These are set to 30 seconds.)

2. The circular buffer used when transferring the file to the server has a timeout when pushing and popping data. (This is set to 30 seconds.)

Should these be configurable or would that be confusing? If not, what is the best setting for these.

• These need to be long enough so that we don't have a timeout during normal operation. (30 seconds is more than enough for this it appears.)
• The shorter these are, the less time it takes for the plugin to notice if something went wrong/crashed.

[trel]

Right, we're not sure yet whether having knobs for these are more helpful than confusing.

IF we were to pull these out, and name them... are these... sufficient?

• timeout_for_optimal_threads_in_seconds
• timeout_for_circular_buffer_in_seconds

And yes, unless we determine otherwise, we'd default to 30 for these if they were not defined.