code: static function release( $token, $mode, $opts=array() )
      {
          // just in case (is_file results might be cached!)...
          clearstatcache();
  
          $lockDir = self::lockDir( $opts );
          if ( $mode == LOCK_EX )
          {
              $wLockFile = "$lockDir/{$token}_W.lock";
              if ( is_file(  $wLockFile ) && !unlink( $wLockFile ) )
              {
                  // what to do here? we echo an error msg but do not throw an exception
                  pake_echo_error( "Could not remove W lock file '$wLockFile'" );
              }
              return;
          }
          // assume a read lock
          $rLockFile = "$lockDir/{$token}_R/" . getmypid() . ".lock";
          if ( is_file(  $rLockFile ) && !unlink( $rLockFile ) )
          {
              // what to do here? we echo an error msg but do not throw an exception
              pake_echo_error( "Could not remove R lock file '$rLockFile'" );
          }
      }
docs: Releases the token. Does not warn if lock has disappeared before the release.
  @param string $token
  @param int $mode
  @param array $opts