rust-reqwest-stream-example.rs

let offset = 20000;
let chunk_size = 10000;

// File handle:
let mut handle = BufReader::new(File::open("data.bin").await?);

// Set cursor to needed chunk:
let mut chunk_stream = handle
    .bytes()
    .skip(offset)
    .take(chunk_size);

// Error: the trait `std::convert::From<u8>` is not implemented for `bytes::bytes::Bytes`

// See: https://github.com/seanmonstar/reqwest/blob/master/src/async_impl/body.rs#L90

let chunk = multipart::Part::stream(Body::wrap_stream(chunk_stream));
                                   // ^^^^^^^^^^^^^^^

let form = multipart::Form::new()
    .text("session_id", "<session-id>")
    .part("chunk", chunk);


reqwest::Client::new()
    .post("<endpoint>"))
    .multipart(form)
    .send()
    .await?;