refactor: use foreign-type for request

[ensh63]

Proposed changes

foreign_type::ForeignTypeRef trait is used to define Request object. While generally the use of this object almost unchanged, reference trait allows to avoid unnecessary copying of original ngx_http_request_t data.

Checklist

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[Copilot]

Pull Request Overview

This PR refactors the Request struct to use the foreign_types::ForeignTypeRef trait instead of direct wrapper implementation. This change allows the Request object to avoid unnecessary copying of original ngx_http_request_t data by using a reference-based approach.

Key changes:

• Replace direct struct wrapping with ForeignTypeRef trait implementation
• Update all macro call sites to use ForeignTypeRef::from_ptr_mut() instead of custom conversion
• Add foreign-types dependency to enable the new pattern

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/http/request.rs	Refactored Request struct to implement ForeignTypeRef trait and updated all field access to use helper methods
src/http/upstream.rs	Updated macro to use ForeignTypeRef::from_ptr_mut() for request conversion
src/core/mod.rs	Added re-export of ForeignTypeRef trait
examples/upstream.rs	Updated example to use new ForeignTypeRef pattern and added import
examples/async.rs	Updated async example to use ForeignTypeRef conversion methods
Cargo.toml	Added foreign-types dependency

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[pchickey]

I agree that Request(ngx_http_request_t) was the wrong representation. I was going to propose that we make it Request(NonNull<ngx_http_request_t>) with a constructor fn from_http_request(NonNull<ngx_http_request_t>) -> Self and not use any &mut self methods, because nginx does not consider any *mut ngx_http_request_t to be unique, and the uniqueness property of Request does not make its use any more or less unsafe.

[xeioex]

LGTM.