Support async for bulk operations

[pjbull]

Lots of what we do in _to_apply here is either going to be disk (in the case of Path) or network (if we implement #1) bound and should benefit from doing it async.

pandas-path/pandas_path/accessor.py

Lines 77 to 105 in 8b7d147

	def _elementwise(self, other, attr):
	if isinstance(other, PathAccessor):
	other = other._obj
	other_array = np.array(other)
	if other_array.ndim > 1:
	raise ValueError(
	"Can only do an elementwise operations with a 1d array, list, or Series."
	)
	if other_array.shape[0] != len(self._obj):
	raise ValueError(
	"Can only do an elementwise operation with arrays of the same length."
	)
	def _to_apply(this_elem, other_elem):
	res = getattr(Path(this_elem), attr)(other_elem)
	return res if not isinstance(res, Path) else str(res)
	elementwise_result = pd.Series(
	[
	_to_apply(this_elem, other_elem)
	for this_elem, other_elem in zip(self._obj.values, other_array)
	],
	index=self._obj.index,
	)
	return elementwise_result