public static byte[] serializeToBlob(Object obj, KnownVersion version) throws IOException {
    final long start = startSerialization();
    byte[] result;
    try (HeapDataOutputStream hdos = new HeapDataOutputStream(version)) {
      DataSerializer.writeObject(obj, hdos);
      result = hdos.toByteArray();
    }
    endSerialization(start, result.length);
    return result;
  }
A blob is a serialized Object. This method serializes the object into a blob and returns the
byte array that contains the blob.
geode-core/src/main/java/org/apache/geode/internal/util/BlobHelper.java