This repository is a Go HTTP client library named 'req' (module github.com/imroc/req/v3). It provides a high-level, fluent API for making HTTP requests with extensive features including HTTP/1.1, HTTP/2, and HTTP/3 support, automatic retries with configurable backoff and conditions, middleware chains for request/response processing, TLS fingerprint impersonation (via uTLS), bandwidth rate limiting, parallel file downloads, digest authentication, and detailed debugging capabilities (dump, trace, curl command generation). The library is designed for production use, with a focus on ease of use and flexibility, allowing developers to build custom SDKs on top of it. The architecture centers around a Client struct that holds configuration and a Transport that wraps net/http with additional capabilities. Requests are built using a builder pattern (R() method) and executed via method-specific helpers (Get, Post, etc.). The codebase includes a significant amount of internal code forked from Go's standard library (HTTP/2, chunked encoding) and third-party dependencies (quic-go for HTTP/3, brotli, zstd). It is a pure application library with no data analysis or research components.