}

      // Read either \r\n or --\r\n to determine if there is another part.
      var whitespace = false
      afterBoundaryLoop@while (true) {
        when (source.select(afterBoundaryOptions)) {
          0 -> {
            // "\r\n": We've found a new part.
            partCount++
            break@afterBoundaryLoop
          }

          1 -> {