override def buildScan()

in connector/src/main/scala/com/microsoft/kusto/spark/datasource/KustoRelation.scala [60:101]
30 lines of code
5 McCabe index (conditional complexity)

  override def buildScan(requiredColumns: Array[String], filters: Array[Filter]): RDD[Row] = {
    val kustoClient = KustoClientCache.getClient(
      kustoCoordinates.clusterUrl,
      authentication,
      kustoCoordinates.ingestionUrl,
      kustoCoordinates.clusterAlias)
    val isUserOptionForceSingleMode = readOptions.readMode.contains(ReadMode.ForceSingleMode)
    val (useSingleMode, estimatedRecordCount) = readOptions.readMode match {
      // if the user provides a specific option , this is to be used no matter what
      case Some(_) => (isUserOptionForceSingleMode, -1)
      // If there is no option mentioned , then estimate which option to use
      // Count records and see if we wat a distributed or single mode
      case None =>
        val estimatedRecordCountResult = Try(
          KDSU.estimateRowsCount(
            kustoClient.engineClient,
            query,
            kustoCoordinates.database,
            clientRequestProperties.orNull))
        /*
        Return values of estimate method
        - Non zero integer : In case estimate method returns a value , estimated result
        - Zero : Estimate fails and falls back to count , this gives a 0 result
        - An exception : Happens when estimate is a null/empty and we fallback to count and count fails as well (timeout)
         */
        estimatedRecordCountResult match {
          // if the count is lss than the 5k threshold,use single mode.
          case Success(recordCount) =>
            (recordCount <= KustoConstants.DirectQueryUpperBoundRows, recordCount)
          // A case of query timing out. ForceDistributedMode will be used here
          case Failure(_) => (false, -1)
        }
    }
    // To avoid all the complexity and logically split , extract this to a separate API
    buildScanImpl(
      requiredColumns,
      filters,
      kustoClient,
      isUserOptionForceSingleMode,
      useSingleMode,
      estimatedRecordCount)
  }