+/* Creates a new pvconn named 'name' that will accept new socket connections on
+ * 'fd' and stores a pointer to the vconn in '*pvconnp'.
+ *
+ * When a connection has been accepted, 'accept_cb' will be called with the new
+ * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
+ * accept_cb must return 0 if the connection is successful, in which case it
+ * must initialize '*vconnp' to the new vconn, or a positive errno value on
+ * error. In either case accept_cb takes ownership of the 'fd' passed in.
+ *
+ * When '*pvconnp' is closed, then 'unlink_path' (if nonnull) will be passed to
+ * fatal_signal_unlink_file_now() and freed with free().
+ *
+ * Returns 0 if successful, otherwise a positive errno value. (The current
+ * implementation never fails.) */