private void write(OplogFile olf, byte[] bytes, int byteLength) {
      int offset = 0;
      ByteBuffer bb = olf.writeBuf;
      while (offset < byteLength) {

        int bytesThisTime = byteLength - offset;
        boolean needsFlush = false;
        if (bytesThisTime > bb.remaining()) {
          needsFlush = true;
          bytesThisTime = bb.remaining();
        }
        bb.put(bytes, offset, bytesThisTime);
        offset += bytesThisTime;
        if (needsFlush) {
          flushNoSync();
        }
      }
    }
How many bytes it will be when serialized
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java