+namespace simgrid {
+/** @brief Modeling of the availability profile (due to an external load) or the churn
+ *
+ * There is 4 main concepts in this module:
+ * - #DatedValue: a pair <timestamp, value> (both are of type double)
+ * - #trace: a list of dated values
+ * - #trace_event: links a given trace to a given SimGrid resource.
+ * A Cpu for example has 2 kinds of events: state (ie, is it ON/OFF) and speed,
+ * while a link has 3 iterators: state, bandwidth and latency.
+ * - #future_evt_set: makes it easy to find the next occuring event of all traces
+ */
+namespace trace_mgr {
+class XBT_PUBLIC DatedValue {
+public:
+ double date_ = 0;
+ double value_ = 0;
+ explicit DatedValue() = default;
+ explicit DatedValue(double d, double v) : date_(d), value_(v) {}
+ bool operator==(DatedValue e2);
+ bool operator!=(DatedValue e2) { return not(*this == e2); }
+};
+std::ostream& operator<<(std::ostream& out, const DatedValue& e);
+
+/** @brief A trace_iterator links a trace to a resource */
+class XBT_PUBLIC trace_event {
+};