private void writeOrdinal(OplogFile olf, short ordinal) {
      ByteBuffer bb = olf.writeBuf;
      if (3 > bb.remaining()) {
        flushNoSync();
      }
      // don't compress since we setup fixed size of buffers
      VersioningIO.writeOrdinal(bb, ordinal, false);
    }
How many bytes it will be when serialized
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java