Async_unix includes Unix-related dependencies for things like system calls and threads. Using these, it hooks the Async_kernel scheduler up to either epoll or select, depending on availability, and manages a thread pool that blocking system calls run in.
Binary packages can be installed with the high-level tool pkgin (which can be installed with pkg_add) or pkg_add(1) (installed by default). The NetBSD packages collection is also designed to permit easy installation from source.
The pkg_admin audit command locates any installed package which has been mentioned in security advisories as having vulnerabilities.
Please note the vulnerabilities database might not be fully accurate, and not every bug is exploitable with every configuration.
Problem reports, updates or suggestions for this package should be reported with send-pr.