- use 'next_flush_time' as a time.Time instead of computing   duration-since-last-flush-or-start; I think it makes the code more   readable to say "is the current time after next_flush_time?"
- use 'next_flush_time' as a time.Time instead of computing
  duration-since-last-flush-or-start; I think it makes the code more
  readable to say "is the current time after next_flush_time?"

scrapinghub/log-courier,linearregression/log-courier,linearregression/log-courier,scrapinghub/log-courier,dixitk13/log-courier,srizzling/log-courier,MichaelLiZhou/log-courier,dixitk13/log-courier,scrapinghub/log-courier,linearregression/log-courier,MichaelLiZhou/log-courier,dixitk13/log-courier,srizzling/log-courier,srizzling/log-courier,MichaelLiZhou/log-courier