Class which can make any IO object rewindable, including non-rewindable ones. It does this by buffering the data into a tempfile, which is rewindable.

rack.input is required to be rewindable, so if your input stream IO is non-rewindable by nature (e.g. a pipe or a socket) then you can wrap it in an object of this class to easily make it rewindable.

Don‘t forget to call close when you‘re done. This frees up temporary resources that RewindableInput uses, though it does not close the original IO object.