Ruby concurrency library developed by Sharon Rosner for roughly a year prior to wroclove.rb 2026. A UringMachine instance is an io_uring instance paired with a run queue; it controls fiber lifetimes and exposes a low-level API closely mirroring the normal IO syscall interface (raw file descriptors and caller-provided buffers), plus higher-level abstractions: a UringMachine::IO class with buffered reads, a fiber scheduler implementation compatible with Ruby 3.0+ Fiber::SchedulerInterface, synchronization primitives (mutexes, queues) built on futex, OpenSSL integration via a custom BIO, and support for Linux-specific interfaces (pidfd, inotify). Supports IO-operation cancellation, universal timeouts, graceful shutdown via Ruby exceptions, multi-shot accept/timeout/read/receive, and fully automatic buffer management built on io_uring provided buffers with incremental consumption and segmented (linked-list) buffers. Named in homage to EventMachine, which it aims to replace.