public File getDrfFile() {
    return drf.f;
  }
Test Method to be used only for testing purposes. Gets the underlying File object for the Oplog
. Oplog class uses this File object to obtain the RandomAccessFile object. Before returning the
File object , the dat present in the buffers of the RandomAccessFile object is flushed.
Otherwise, for windows the actual file length does not match with the File size obtained from
the File object
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java