// by executing on the same thread.
    if (executorService.isShutdown) {
      for (i in 0 until executableCalls.size) {
        val asyncCall = executableCalls[i]
        asyncCall.callsPerHost.decrementAndGet()

        this.withLock {
          runningAsyncCalls.remove(asyncCall)
        }

        asyncCall.failRejected()
      }
      idleCallback?.run()
    } else {