Refactor: make inbound request contextual

constant/adapters.go

@@ -27,11 +27,6 @@ const (
 	LoadBalance
 )
 
-type ServerAdapter interface {
-	net.Conn
-	Metadata() *Metadata
-}
-
 type Connection interface {
 	Chains() Chain
 	AppendToChains(adapter ProxyAdapter)
@@ -50,6 +45,15 @@ func (c Chain) String() string {
 	}
 }
 
+func (c Chain) Last() string {
+	switch len(c) {
+	case 0:
+		return ""
+	default:
+		return c[0]
+	}
+}
+
 type Conn interface {
 	net.Conn
 	Connection