commonlib/src/main/java/com/streamsets/pipeline/lib/util/AvroSchemaHelper.java
public int writeSchemaId(OutputStream os, int schemaId) throws IOException {
    if (schemaId > 0) {
      os.write(MAGIC_BYTE);
      os.write(ByteBuffer.allocate(ID_SIZE).putInt(schemaId).array());
    }
    return schemaId;
  }
public int writeSchemaId(OutputStream os, int schemaId) throws IOException {
    if (schemaId > 0) {
      os.write(MAGIC_BYTE);
      os.write(ByteBuffer.allocate(ID_SIZE).putInt(schemaId).array());
    }
    return schemaId;
  }
Writes the magic byte and schema ID to an output stream, replicating the functionality
of the Confluent Kafka Avro Serializer
@param os OutputStream to write to
@return schema ID that was written
@throws IOException if there is an error