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/session_test.go

@@ -67,6 +67,27 @@ func TestSession_Insert(t *testing.T) {
 			},
 			expectLog: false,
 		},
+		{
+			name: "sampling",
+			filters: StreamingFilters{
+				Sampling: 0.9999999,
+			},
+			expectLog: true,
+		},
+		{
+			name: "sampling (invalid negative)",
+			filters: StreamingFilters{
+				Sampling: -1.0,
+			},
+			expectLog: true,
+		},
+		{
+			name: "sampling (invalid too large)",
+			filters: StreamingFilters{
+				Sampling: 2.0,
+			},
+			expectLog: true,
+		},
 		{
 			name: "filter and event",
 			filters: StreamingFilters{