parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetFileWriter.java
static GlobalMetaData mergeInto(
      FileMetaData toMerge,
      GlobalMetaData mergedMetadata) {
    return mergeInto(toMerge, mergedMetadata, true);
  }
static GlobalMetaData mergeInto(
      FileMetaData toMerge,
      GlobalMetaData mergedMetadata) {
    return mergeInto(toMerge, mergedMetadata, true);
  }
Will return the result of merging toMerge into mergedMetadata
@param toMerge the metadata toMerge
@param mergedMetadata the reference metadata to merge into
@return the result of the merge