+/**
+ * Simple pre-select hook, used by all receivers.
+ *
+ * \param s Scheduler info.
+ * \param t Determines the receiver node.
+ *
+ * This requests a minimal delay from the scheduler if the status of the buffer
+ * tree node indicates an error/eof condition. No file descriptors are added to
+ * the fd sets of \a s.
+ *
+ * \return Standard.
+ */