+ *
+ * Example:
+ * #include <sys/types.h>
+ * #include <sys/time.h>
+ * #include <sys/resource.h>
+ * #include <sys/wait.h>
+ *
+ * static void wait_for_child(struct lbalance_task *task)
+ * {
+ * struct rusage ru;
+ * // Wait for child to finish, get usage.
+ * wait4(-1, NULL, 0, &ru);
+ * // Tell lbalancer about usage, free struct lbalance_task.
+ * lbalance_task_free(task, &ru);
+ * }