+/**
+ * io_conn_exclusive - set/unset an io_conn to exclusively serviced
+ * @conn: the connection
+ * @exclusive: whether to be exclusive or not
+ *
+ * If any io_conn is set exclusive, then no non-exclusive io_conn (or
+ * io_listener) will be serviced by io_loop(). If it's a io_duplex io_conn(),
+ * then io_conn_exclusive() makes the read-side exclusive; io_conn_out_exclusive()
+ * makes the write-side exclusive.
+ *
+ * This allows you to temporarily service only one (or several) fds.
+ * For example, you might want to flush out one io_conn and not
+ * receive any new connections or read any other input.
+ *
+ * Returns true if any exclusive io_conn remain, otherwise false.
+ * (This is useful for checking your own logic: dangling exclusive io_conn
+ * are dangerous!).
+ */
+bool io_conn_exclusive(struct io_conn *conn, bool exclusive);
+
+/**
+ * io_conn_out_exclusive - set/unset exclusive on the write-side of a duplex
+ * @conn: the connection, post io_duplex
+ * @exclusive: whether to be exclusive or not
+ *
+ * See io_conn_exclusive() above.
+ */
+bool io_conn_out_exclusive(struct io_conn *conn, bool exclusive);
+
+/**
+ * io_fd_block - helper to set an fd blocking/nonblocking.
+ * @fd: the file descriptor
+ * @block: true to set blocking, false to set non-blocking.
+ *
+ * Generally only fails is @fd isn't a valid file descriptor, otherwise
+ * returns true.
+ */
+bool io_fd_block(int fd, bool block);
+