class_docstr: A GenomicsWriter that dispatches based on the file extension.
  
  If '.tfrecord' is present in the filename, a TFRecordWriter is used.
  Otherwise, a native writer is.
  
  Sub-classes of DispatchingGenomicsWriter must define a _native_writer()
  method.
class_docstr_tok: ["A","GenomicsWriter","that","dispatches","based","on","the","file","extension",".","If","'.tfrecord","'","is","present","in","the","filename",",","a","TFRecordWriter","is","used",".","Otherwise",",","a","native","writer","is",".","Sub-classes","of","DispatchingGenomicsWriter","must","define","a","_native_writer","(",")","method","."]
docstr: Hook for subclasses to run code at the end of __init__.
docstr_tok: ["Hook","for","subclasses","to","run","code","at","the","end","of","__init__","."]
code: def _post_init_hook(self):
      """Hook for subclasses to run code at the end of __init__."""
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import abc
  import errno
  from absl import logging
  from third_party.nucleus.io.python import tfrecord_writer
label_desc: Use image node_id 6 for calling the DispatchingGenomicsWriter obj's underlying member method code with example usage: obj._post_init_hook() without return types