mensfeld/pidfd: Pidfd implementation for the Ruby language

A Ruby wrapper for Linux pidfd (Process File Descriptor) system calls, providing safer process management with guaranteed process identity. What is pidfd? Process file descriptors (pidfd) were introduced in Linux 5.3 (2019) to solve fundamental problems with traditional PID-based process management: The Problem with PIDs Traditional Unix PIDs have a critical flaw: PID reuse. When a process dies, its PID can be immediately reassigned to a new, unrelated process. This creates race conditions where: You might send signals to the wrong process Process state checks become unreliable Security vulnerabilities can arise from PID confusion.