This class can be used to convert an iterable object into
an iterable that will only yield a piece of the underlying content.
It yields blocks until the underlying stream range is fully read.
The yielded blocks will have a size that can't exceed the original
iterator defined block size, but that can be smaller.
If you're using this object together with a :class:`BaseResponse` you have
to use the `direct_passthrough` mode.
:param iterable: an iterable object with a :meth:`__next__` method.
:param start_byte: byte from which read will start.
:param byte_range: how many bytes to read.