multipartStream function
Hands a multipart/form-data body over a part at a time, without buffering.
For uploads too large to hold in memory. The parts are ordered and consumable once; use multipart when you need to read them out of order.
Implementation
FromRequest<StreamedMultipart> multipartStream(
{int limit = 64 * 1024 * 1024}) =>
StreamedMultipartExtractable(limit: limit);