use a semaphore to make sure we're not sending in more work than is coming out. fixes https://github.com/brentp/vcfanno/issues/9
use a semaphore to make sure we're not sending in more work than is
coming out. fixes https://github.com/brentp/vcfanno/issues/9

brentp/irelate,brentp/irelate,brentp/irelate