Problem
There's no multipart body type, which form/file uploads need.
Proposed change
Add a MultipartRequestBody writing to a BufferedSink, with a single shared frame-size function used by both writeTo and contentLength (avoid two independent literals drifting). File parts stream zero-copy via FileRequestBody; non-file parts serialize via the Serde SPI. No Jackson in core.
Acceptance
Priority: medium · Effort: large
Problem
There's no multipart body type, which form/file uploads need.
Proposed change
Add a
MultipartRequestBodywriting to aBufferedSink, with a single shared frame-size function used by bothwriteToandcontentLength(avoid two independent literals drifting). File parts stream zero-copy viaFileRequestBody; non-file parts serialize via theSerdeSPI. No Jackson in core.Acceptance
contentLengthmatcheswriteToPriority: medium · Effort: large