code: public void activate() {
          // if no handlers are currently running, start one now
          if (this.numHandlersInFlight.getInt() == 0) {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                  Tr.debug(tc, "Activating result handler: " + this.completionPort);
              }
              startHandler();
          }
      }
docs: Activate the result handler when the channel starts.