fix: debounce stopwatch and timer

This keeps them from ticking too fast.

Fixes #661.

timer/timer.go

@@ -61,6 +61,8 @@ type TickMsg struct {
 	// Timeout returns whether or not this tick is a timeout tick. You can
 	// alternatively listen for TimeoutMsg.
 	Timeout bool
+
+	tag int
 }
 
 // TimeoutMsg is a message that is sent once when the timer times out.
@@ -80,6 +82,7 @@ type Model struct {
 	Interval time.Duration
 
 	id      int
+	tag     int
 	running bool
 }
 
@@ -137,6 +140,13 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 			break
 		}
 
+		// If a tag is set, and it's not the one we expect, reject the message.
+		// This prevents the ticker from receiving too many messages and
+		// thus ticking too fast.
+		if msg.tag > 0 && msg.tag != m.tag {
+			return m, nil
+		}
+
 		m.Timeout -= m.Interval
 		return m, tea.Batch(m.tick(), m.timedout())
 	}
@@ -166,7 +176,7 @@ func (m *Model) Toggle() tea.Cmd {
 
 func (m Model) tick() tea.Cmd {
 	return tea.Tick(m.Interval, func(_ time.Time) tea.Msg {
-		return TickMsg{ID: m.id, Timeout: m.Timedout()}
+		return TickMsg{ID: m.id, tag: m.tag, Timeout: m.Timedout()}
 	})
 }