This repository is `imroc/req`, a feature-rich, production-grade HTTP client library for Go (version 3). It provides a high-level fluent API for building and executing HTTP requests with support for HTTP/1.1, HTTP/2, and HTTP/3 (via QUIC). Key capabilities include connection pooling, automatic retries with configurable backoff, redirect policies, request/response middleware, TLS fingerprint impersonation (mimicking Chrome, Firefox, Safari), SOCKS4/4a/5 proxying, compression (gzip, deflate, brotli, zstd), response body auto-decode (charset detection), file upload/download with progress callbacks, parallel downloading, and extensive debugging via request/response dump and trace. The library is built on top of Go's `net/http` transport but extends it significantly with custom implementations for HTTP/2 frames, HTTP/3, and SOCKS. It is designed for both simple API calls and complex integrations, as demonstrated by included examples for OpenTelemetry tracing and GitHub API usage. The codebase is well-tested and actively maintained, targeting recent Go versions (1.25+). While primarily an HTTP client library, it includes self-contained utility packages for charset detection, SOCKS proxy, and compression that could be reused independently.