Because the buffers are `MaybeUninit<V8Slice<u8>`, and the owner of the
`BoundedBufferChannel` is not obligated to read each and every bit of
data, we may find that some buffers were not automatically dropped if
unread by the time the `BoundedBufferChannelInner` is dropped.
Possible repro:
```
Deno.serve(() => new Response(new ReadableStream({ start(controller) { controller.enqueue(new Uint8Array(100_000_000)) } })));
```
```bash
while true; do curl localhost:8000 | dd count=1; done
```
Switch `ext/fetch` over to `resourceForReadableStream` to simplify and
unify implementation with `ext/serve`. This allows us to work in Rust
with resources only.
Two additional changes made to `resourceForReadableStream` were
required:
- Add an optional length to `resourceForReadableStream` which translates
to `size_hint`
- Fix a bug where writing to a closed stream that was full would panic
We can go one level down in abstraction and avoid using the public
`ReadableStream` APIs.
This patch ~5% perf boost on small ReadableStream:
```
Running 10s test @ http://localhost:8080/
2 threads and 10 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 148.32us 108.95us 3.88ms 95.71%
Req/Sec 33.24k 2.68k 37.94k 73.76%
668188 requests in 10.10s, 77.74MB read
Requests/sec: 66162.91
Transfer/sec: 7.70MB
```
main:
```
Running 10s test @ http://localhost:8080/
2 threads and 10 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 150.23us 67.61us 4.39ms 94.80%
Req/Sec 31.81k 1.55k 35.56k 83.17%
639078 requests in 10.10s, 74.36MB read
Requests/sec: 63273.72
Transfer/sec: 7.36MB
```
Fixes: #20569 by introducing a custom replacement for the tokio mpsc
channel that is byte-size backpressure-aware.
Using the testcase in the linked bug, we see all the small writes
aggregated into a single packet and HTTP frame.
```
10:39 $ nc localhost 8000
GET / HTTP/1.1
HTTP/1.1 200 OK
content-type: text/plain
vary: Accept-Encoding
transfer-encoding: chunked
date: Tue, 19 Sep 2023 16:39:13 GMT
A
0
1
2
3
4
```
This patch:
```
Running 10s test @ http://localhost:8080/
2 threads and 10 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 157.47us 194.89us 9.53ms 98.97%
Req/Sec 31.37k 1.56k 34.73k 85.15%
630407 requests in 10.10s, 73.35MB read
Requests/sec: 62428.12
Transfer/sec: 7.26MB
```
main:
```
Running 10s test @ http://localhost:8080/
2 threads and 10 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 343.75us 200.48us 10.41ms 98.25%
Req/Sec 14.64k 806.52 16.98k 84.65%
294018 requests in 10.10s, 39.82MB read
Requests/sec: 29109.91
Transfer/sec: 3.94MB
```
---------
Co-authored-by: Bert Belder <bertbelder@gmail.com>
<!--
Before submitting a PR, please read https://deno.com/manual/contributing
1. Give the PR a descriptive title.
Examples of good title:
- fix(std/http): Fix race condition in server
- docs(console): Update docstrings
- feat(doc): Handle nested reexports
Examples of bad title:
- fix #7123
- update docs
- fix bugs
2. Ensure there is a related issue and it is referenced in the PR text.
3. Ensure there are tests that cover the changes.
4. Ensure `cargo test` passes.
5. Ensure `./tools/format.js` passes without changing files.
6. Ensure `./tools/lint.js` passes.
7. Open as a draft PR if your work is still in progress. The CI won't
run
all steps, but you can add '[ci]' to a commit message to force it to.
8. If you would like to run the benchmarks on the CI, add the 'ci-bench'
label.
-->
As the title.
---------
Co-authored-by: Matt Mastracci <matthew@mastracci.com>
