Introduces exponential backoff into RetryOnError.wrap.
Removes Errno::EADDRNOTAVAIL from HasFixity::RETRIABLE_IO_ERRORS because it's not really an I/O and probably isn't arising in those wrapped blacks anyway.
Removes Errno::EADDRNOTAVAIL from HasFixity::RETRIABLE_IO_ERRORS because it's not really an I/O and probably isn't arising in those wrapped blacks anyway.