parquet-hadoop/src/main/java/org/apache/parquet/hadoop/MemoryManager.java
synchronized void addWriter(InternalParquetRecordWriter writer, Long allocation) {
    Long oldValue = writerList.get(writer);
    if (oldValue == null) {
      writerList.put(writer, allocation);
    } else {
      throw new IllegalArgumentException("[BUG] The Parquet Memory Manager should not add an " +
          "instance of InternalParquetRecordWriter more than once. The Manager already contains " +
          "the writer: " + writer);
    }
    updateAllocation();
  }
synchronized void addWriter(InternalParquetRecordWriter writer, Long allocation) {
    Long oldValue = writerList.get(writer);
    if (oldValue == null) {
      writerList.put(writer, allocation);
    } else {
      throw new IllegalArgumentException("[BUG] The Parquet Memory Manager should not add an " +
          "instance of InternalParquetRecordWriter more than once. The Manager already contains " +
          "the writer: " + writer);
    }
    updateAllocation();
  }
Add a new writer and its memory allocation to the memory manager.
@param writer the new created writer
@param allocation the requested buffer size