code: public void stop() {
          synchronized (lock) {
              Log.i(DOMAIN, "%s: Replicator is stopping ...", this);
              if (c4repl != null) {
                  c4repl.stop(); // this is async; status will change when repl actually stops
              }
              else { Log.i(DOMAIN, "%s: Replicator has been stopped or offlined ...", this); }
  
              if (c4ReplStatus.getActivityLevel() == C4ReplicatorStatus.ActivityLevel.OFFLINE) {
                  Log.i(DOMAIN, "%s: Replicator has been offlined; " +
                      "make the replicator into the stopped state now.", this);
                  final C4ReplicatorStatus c4replStatus = new C4ReplicatorStatus();
                  c4replStatus.setActivityLevel(C4ReplicatorStatus.ActivityLevel.STOPPED);
                  this.c4StatusChanged(c4replStatus);
              }
  
              if (reachabilityManager != null) { reachabilityManager.removeNetworkReachabilityListener(this); }
          }
      }
docs: Stops a running replicator. This method returns immediately; when the replicator actually
  stops, the replicator will change its status's activity level to `kCBLStopped`
  and the replicator change notification will be notified accordingly.