Automatic support for *_proxy

[jerome-jutteau]

Hi,

Several tools would need to have support for proxy. The easiest way to globally add this support is to add it to SDKs.

When talking about proxy support, we are talking more precisely about those env variables:

• http_proxy / HTTP_PROXY
• https_proxy / HTTPS_PROXY
• no_proxy / NO_PROXY

(notes about no_proxy)

Rust sdk uses reqwest which seems to have native proxy support enabled by default:

System proxies are enabled by default
System proxies look in environment variables to set HTTP or HTTPS proxies.

For some reason, those proxy variables seems not to be used as is in osc-cost (see #97).

SDK examples seems to suffer the same problem as well.

[jerome-jutteau]

Seems like the Rust SDK generator uses reqwest 0.9.24 which does not support system proxy by default but can be enabled using use_sys_proxy. Doc adds:

** NOTE** System proxies will be used in the next breaking change.

Two options:

• Upgrade generator: may cause breaking change and some security issues are spoted
• Stick on this reqwest version but patch SDK post-generation to include use_sys_proxy() in request builder.