TUN-7133: Add sampling support for streaming logs

In addition to supporting sampling support for streaming logs,
cloudflared tail also supports this via `--sample 0.5` to sample 50%
of your log events.

management/events_test.go

@@ -57,13 +57,23 @@ func TestIntoClientEvent_StartStreaming(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "sampling filter",
+			expected: EventStartStreaming{
+				ClientEvent: ClientEvent{Type: StartStreaming},
+				Filters: &StreamingFilters{
+					Sampling: 0.5,
+				},
+			},
+		},
 		{
 			name: "level and events filters",
 			expected: EventStartStreaming{
 				ClientEvent: ClientEvent{Type: StartStreaming},
 				Filters: &StreamingFilters{
-					Level:  infoLevel,
-					Events: []LogEventType{Cloudflared},
+					Level:    infoLevel,
+					Events:   []LogEventType{Cloudflared},
+					Sampling: 0.5,
 				},
 			},
 		},