No matter what configs I try, nginx still keeps buffering my requests.

These are the configs that I apply in my test:
```
proxy_pass http://localhost:80;
proxy_request_buffering off;
proxy_buffer_size 4k;
proxy_buffers 8 4k;
proxy_no_cache 1;
proxy_set_header Host $host;
proxy_max_temp_file_size 0;```

in my case I run nodejs app directly on port 80 and I run nginx on 8080, then I run my tests against proxied and direct version.

My nodejs app needs to know exact amount of data that was sent to remote (to calculate speed of transfer and for billing purposes). Ideally, I'd like to know number of ACKed bytes of a TCP connection. Node itself cannot even provide that (as this wasn't even possible until recently on windows).

In my first test I serve 25MB test binary data. Without `proxy_max_temp_file_size 0` nginx would read all 25MB in 5ms and then would continue sending that data to the originator on its own without me (e.g. my node app) ever knowing if all 25MB were delivered or transfer was aborted after 1MB.
After I applied all these configs above this started to work better, and since I proxy in http1.0 mode I can use connection.close event on my node app as a rough approximation when connection was completed.

However, when I send for example 500KB of binary data, nginx still reads in all the data in couple of milliseconds and closes connection and there is no way for me to know on node side if that data was actually properly delivered.
For the test I download that data using wget and I use --limit-rate=10000 to limit download on receiver side to 10KB/s. After 5 seconds I ctrl+C and abort transfer after loading just 50KB, while my nodejs side actually thinks that everything went well and all 500KB were loaded.


1) how can I make nginx not to buffer more than 64KB of data?
2) can my node app know how much data nginx ended up delivering?