Cache OCSP response within one run
Within a single run, if multiple threads access the same domain, then each thread attempts to contact the OCSP server for that domain. However, if one of them succeeds, we should assume that all of them will succeed. The chance of a certificate being revoked within those couple of seconds is extremely minimal.
It may make sense for only one thread to contact the OCSP server, and block the others. This should also reduce the bandwidth usage. The response should then be cached in case another thread in the future contacts the same domain