(pstreambuf::wait()): Fix resource leaks when wait() called before close(). (pstreambuf::sync()): Use exited() to avoid writing to exited process.
(pstreambuf::wait()): Fix resource leaks when wait() called before close().
(pstreambuf::sync()): Use exited() to avoid writing to exited process.

zmij/tip-http,zmij/tip-http,zmij/tip-http,zmij/pg_async,zmij/tip-http