fn poll_write()

in src/buffered.rs [375:421]
47 lines of code
4 McCabe index (conditional complexity)

    fn poll_write(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<Result<usize, Error>> {
        let cap = self.capacity;
        let max_concurrency = self.max_concurrency;
        loop {
            return match &mut self.state {
                BufWriterState::Write(Some(write)) => {
                    ready!(write.poll_for_capacity(cx, max_concurrency))?;
                    write.write(buf);
                    Poll::Ready(Ok(buf.len()))
                }
                BufWriterState::Write(None) | BufWriterState::Flush(_) => {
                    panic!("Already shut down")
                }
                BufWriterState::Prepare(f) => {
                    self.state = BufWriterState::Write(ready!(f.poll_unpin(cx)?).into());
                    continue;
                }
                BufWriterState::Buffer(path, b) => {
                    if b.content_length().saturating_add(buf.len()) >= cap {
                        let buffer = std::mem::take(b);
                        let path = std::mem::take(path);
                        let opts = PutMultipartOpts {
                            attributes: self.attributes.take().unwrap_or_default(),
                            tags: self.tags.take().unwrap_or_default(),
                            extensions: self.extensions.take().unwrap_or_default(),
                        };
                        let store = Arc::clone(&self.store);
                        self.state = BufWriterState::Prepare(Box::pin(async move {
                            let upload = store.put_multipart_opts(&path, opts).await?;
                            let mut chunked = WriteMultipart::new_with_chunk_size(upload, cap);
                            for chunk in buffer.freeze() {
                                chunked.put(chunk);
                            }
                            Ok(chunked)
                        }));
                        continue;
                    }
                    b.extend_from_slice(buf);
                    Poll::Ready(Ok(buf.len()))
                }
            };
        }
    }