static LongStream buildValidChunkSizeStream(long totalSize, int maxChunkSize) {
    int numChunks = RouterUtils.getNumChunksForBlobAndChunkSize(totalSize, maxChunkSize);
    return LongStream.range(0, numChunks)
        .map(index -> index == numChunks - 1 ? totalSize - (maxChunkSize * index) : maxChunkSize);
  }
@param totalSize the total size of the composite blob.
@param maxChunkSize the size to use for intermediate data chunks.
@return a {@link LongStream} that returns valid chunk sizes that conform to {@code totalSize} and
        {@code maxChunkSize}
ambry-router/src/test/java/com/github/ambry/router/RouterTestHelpers.java