DataChecksum requestedChecksum,
final CachingStrategy cachingStrategy) throws IOException {
ClientOperationHeaderProto header = DataTransferProtoUtil.buildClientHeader(
blk, clientName, blockToken);
ChecksumProto checksumProto =
DataTransferProtoUtil.toProto(requestedChecksum);
OpWriteBlockProto.Builder proto = OpWriteBlockProto.newBuilder()
.setHeader(header)
.addAllTargets(PBHelper.convert(targets, 1))