autocannon is a high-performance HTTP/1.1 benchmarking tool written in Node.js, inspired by wrk and wrk2. It operates as both a CLI tool and a programmable library. The architecture is centered around a run loop that manages multiple concurrent HTTP clients, each capable of pipelining requests. Key components include a request builder that constructs raw HTTP request buffers, a pipelined request queue for handling out-of-order responses, and a histogram-based statistics engine using hdr-histogram-js with WebAssembly for efficient percentile calculations. The tool supports HTTPS, Unix sockets, multipart forms, HAR file replay, worker threads for parallel execution, rate limiting with coordinated omission correction, and extensive customization via setup functions and event hooks. The codebase is well-structured with clear separation of concerns, comprehensive test coverage, and active maintenance.

close-with-grace is a Node.js library that provides graceful shutdown handling for applications. It listens for system signals (SIGTERM, SIGINT, etc.) and process events (uncaughtException, unhandledRejection, beforeExit), giving applications a configurable timeout to perform cleanup operations before exiting. If the same signal occurs again during cleanup, it forces immediate termination. The library supports both callback and promise-based cleanup functions, custom logging, and the ability to skip specific events. It's designed as a simple, self-contained utility that can be easily integrated into any Node.js application needing reliable shutdown handling.