// Given this:
    def shouldRetry(res: Response): Boolean = ???        // Some responses indicate that a request
    def rawCall(reqs: Seq[Request]): Seq[Response] = ??? // should be retried.
    val MaxRetryLimit: Int = ???

    // Perform this:
    def callWithRetries(reqs: Seq[Request], retryCount: Int = 0): Seq[Response] = {
      val results = rawCall(reqs)
      val retryIndices = results.zipWithIndex.collect { case (res, i) if shouldRetry(res) => i }

      if (retryIndices.isEmpty || retryCount == MaxRetryLimit) {
        results
      } else {
        // Bookkeeping
        val retries = retryIndices.map(reqs)
        val retryResultMap = retryIndices.zip(callWithRetries(retries, retryCount + 1)).toMap

        results.indices.map { i =>
          retryResultMap.get(i) match {
            case Some(res) => res
            case None => results(i)
          }
        }
      }
    }