public void setReadPoint(long offset, Position readPos) {
    readPos.bufferIndex = getBufferIndex(offset);
    readPos.buffer = writeBuffers.get(readPos.bufferIndex);
    readPos.offset = getOffset(offset);
  }
THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety).
serde/src/java/org/apache/hadoop/hive/serde2/WriteBuffers.java