NewStreamingMultipartRequest function that uses io.Pipe to encode multipart data concurrently with the HTTP upload:
Create io.Pipe() - PipeReader for HTTP body, PipeWriter for encoder
Spawn goroutine that encodes multipart data to PipeWriter
HTTP client reads from PipeReader as data is written
Use chunked transfer encoding (no Content-Length required)
This streams the file content directly from source → multipart encoder → HTTP upload without buffering.
NewStreamingMultipartRequest function that uses io.Pipe to encode multipart data concurrently with the HTTP upload:
Create io.Pipe() - PipeReader for HTTP body, PipeWriter for encoder
Spawn goroutine that encodes multipart data to PipeWriter
HTTP client reads from PipeReader as data is written
Use chunked transfer encoding (no Content-Length required)
This streams the file content directly from source → multipart encoder → HTTP upload without buffering.