new Sender(out).readBlock(block, blockToken, clientName, startOffset, len);
//
// Get bytes in block, set streams
//
SocketInputWrapper sin = NetUtils.getInputStream(sock);
ReadableByteChannel ch = sin.getReadableByteChannel();
DataInputStream in = new DataInputStream(sin);
BlockOpResponseProto status = BlockOpResponseProto.parseFrom(
vintPrefixed(in));
checkSuccess(status, sock, block, file);