+/**
+ * @brief Represents a unique ID for a Thread
+ *
+ * The space of unique IDs may need to become a non-compact
+ * or non-zero-indexed set of integers (or even some other
+ * type). So this typedef is used to help identify which is
+ * which, where a simple 'int' is meant to be a compact,
+ * zero-indexed set and a 'thread_id_t' may be another type
+ * entirely.
+ *
+ * @see id_to_int
+ * @see int_to_id
+ */