First working example for throughput, but…

It's way too instable due to timing differences. Ideally it will be able
to produce values much closer to what they really are.

Maybe just an issue with big numbers.

examples/units.rs

@@ -53,24 +53,24 @@ fn work_for_a_long_time_blocking(root: Tree) {
         )),
     );
 
-    fn formatter() -> unit::human::Formatter {
+    fn formatter(decimals: usize) -> unit::human::Formatter {
         let mut f = unit::human::Formatter::new();
-        f.with_decimals(0);
+        f.with_decimals(decimals);
         f
     }
     let mut human_count = root.add_child("item count unknown");
     human_count.init(
         None,
         Some(unit::dynamic_and_mode(
-            unit::Human::new(formatter(), "items"),
+            unit::Human::new(formatter(0), "items"),
             unit::display::Mode::with_throughput(),
         )),
     );
     let mut human_count_max = root.add_child("item count");
     human_count_max.init(
         Some(7_542_241),
         Some(unit::dynamic_and_mode(
-            unit::Human::new(formatter(), "items"),
+            unit::Human::new(formatter(2), "items"),
             unit::display::Mode::with_percentage().and_throughput(),
         )),
     );

src/tree/throughput.rs

@@ -19,12 +19,17 @@ impl State {
         }
     }
     fn update(&mut self, value: progress::Step, elapsed: Duration) -> Option<unit::display::Throughput> {
+        self.aggregate_value_for_observed_duration += value.checked_sub(self.last_value).unwrap_or(0);
+        self.observed += elapsed;
+        self.last_value = value;
         self.throughput()
     }
 
     fn throughput(&self) -> Option<unit::display::Throughput> {
         Some(unit::display::Throughput {
-            value_change_in_timespan: self.aggregate_value_for_observed_duration,
+            value_change_in_timespan: ((self.aggregate_value_for_observed_duration as f64
+                / self.observed.as_secs_f64())
+                * self.desired.as_secs_f64()) as progress::Step,
             timespan: self.desired,
         })
     }