exit_on_start.wat

(module $exit_on_start
  (import "wasi_snapshot_preview1" "proc_exit"
    (func $wasi.proc_exit (param $rval i32)))

  (func (export "_start")
     i32.const 2           ;; push $rval onto the stack
     call $wasi.proc_exit  ;; return a sys.ExitError to the caller
  )
)