Summary: Base64 encoding can easily cause OOMs for large payloads. In the long-term, it would be great to have a way of streaming these responses so we don't allocate 50MB chunks of memory at once. Reviewed By: jknoxville Differential Revision: D17951353 fbshipit-source-id: a5d7b8242892518590ac95c1d9751f24d20dc40e