fix(ext/web): Aggregate small packets for Resource implementation of ReadableStream (#20570)

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>

0 files changed, 0 insertions, 0 deletions