class_docstr: FeatureStorage that asynchronously reads features from a ``numpy.memmap`` object.
code: def fetch(self, indices, device, pin_memory=False, **kwargs):
      return ThreadedFuture(
          target=self._fetch, args=(indices, device, pin_memory)
      )
  
file_path: dgl/python/dgl/storages/numpy.py
imports: import numpy
  from ..None import backend
  from .base import FeatureStorage, register_storage_wrapper, ThreadedFuture
label_desc: Use image node_id 3 for calling the NumpyStorage obj's underlying member method code with example usage: obj.fetch(indices, device, pin_memory) and returns: ThreadedFuture