+ /*
+ * Move the earlier set of events later, to avoid creating
+ * events which precede the Big Bang (aka have negative timestamps).
+ *
+ * Not to any scale, we have something like the following picture:
+ *
+ * DST capture start point
+ * ^
+ * +--- dt_event --+
+ * v
+ * SRC capture start point
+ *
+ * In this case dt_event is positive, src started after dst,
+ * to put src events onto a common timebase we have to move them
+ * forward in time. Naturally, the opposite case is
+ * possible, too: dt_event will be negative, and so we have to
+ * move dst events forward in time by the |dt_event|.
+ * In both cases, we add align_tweak.
+ */