Method mergeMetadata

java/core/src/java/org/apache/orc/OrcFile.java:1273–1278

(Map<String,ByteBuffer> metadata,
                            Reader reader)

  }

  static void mergeMetadata(Map<String,ByteBuffer> metadata,
                            Reader reader) {
    for(String key: reader.getMetadataKeys()) {
      metadata.put(key, reader.getMetadataValue(key));
    }
  }

  /**
   * Merges multiple ORC files that all have the same schema to produce