Add xhttp transport

common/xray/stats/stats.go

@@ -0,0 +1,13 @@
+package stats
+
+// Counter is the interface for stats counters.
+//
+// xray:api:stable
+type Counter interface {
+	// Value is the current value of the counter.
+	Value() int64
+	// Set sets a new value to the counter, and returns the previous one.
+	Set(int64) int64
+	// Add adds a value to the current counter value, and returns the previous value.
+	Add(int64) int64
+}