Fix pending state being used incorrectly, ignore ThrottlingException error, accept more options

[itsmepetrov]

Hi!

This PR fixes two issues:

1. we noticed that sometimes we could see some log records repeated, like so:

   Processed: 500/407210 (took 0.84s)
   Processed: 26000/407210 (took 0.56s)
   Processed: 53500/407210 (took 0.51s)
   Processed: 53500/407210 (took 0.51s) <- double
   Processed: 98500/407210 (took 0.67s)
   Processed: 123500/407210 (took 0.53s)
   Processed: 123500/407210 (took 0.53s)
   Processed: 123500/407210 (took 0.53s) <- triple
   Processed: 152000/407210 (took 0.47s)
   

   it was caused by the pending key not being set correctly, so there was some sort of race condition;
2. because of the race condition we could get ThrottlingException, get logs calls have a hard limit, and they don't qualify for a limit increase in AWS, so having two, three... tasks running simultaneously could cause the error quickly, the easiest way just to ignore it as it do not affect anything.

I've also added configuration for durationBetweenPolls and timeoutBeforeFirstLogs

[itsmepetrov]

@ohookins could you please review it

[ohookins]

@itsmepetrov thanks for the contribution! It's been a bit busy recently but I will review it soon :)

[itsmepetrov]

@ohookins any news?

[ohookins]

@itsmepetrov thanks for your contribution! It seems like this repo has some settings which aren't compatible with external contributions so I need to get them fixed before I can merge your PR. Unless you want to go back and sign your commits?

[ohookins]

Actually I probably do need you to sign the commits, if that's ok.