text: """Feature storage for ``numpy.memmap`` object."""
  import numpy as np
  from .base import FeatureStorage, ThreadedFuture, register_storage_wrapper
  from .. import backend as F
  
  @register_storage_wrapper(np.memmap)
  class NumpyStorage(FeatureStorage):
      """FeatureStorage that asynchronously reads features from a ``numpy.memmap`` object."""
      def __init__(self, arr):
          self.arr = arr
  
      # pylint: disable=unused-argument
      def _fetch(self, indices, device, pin_memory=False):
          result = F.zerocopy_from_numpy(self.arr[indices])
          result = F.copy_to(result, device)
          return result
  
      # pylint: disable=unused-argument
      def fetch(self, indices, device, pin_memory=False, **kwargs):
          return ThreadedFuture(target=self._fetch, args=(indices, device, pin_memory))
  