Add sockopt interface setting for binding outbound to a particular device like "eth0" (#1494)

* Update sockopt_linux.go

add Interface Name

* Update config.pb.go

add Interface Name

* Update transport_internet.go

add Interface Name

* Update config.pb.go

* update config.proto add interface

* Update config.pb.go

infra/conf/transport_internet.go

@@ -534,6 +534,7 @@ type SocketConfig struct {
 	TCPKeepAliveInterval int32       `json:"tcpKeepAliveInterval"`
 	TCPKeepAliveIdle     int32       `json:"tcpKeepAliveIdle"`
 	TCPCongestion        string      `json:"tcpCongestion"`
+	Interface            string      `json:"interface"`
 }
 
 // Build implements Buildable.
@@ -583,6 +584,7 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 		TcpKeepAliveInterval: c.TCPKeepAliveInterval,
 		TcpKeepAliveIdle:     c.TCPKeepAliveIdle,
 		TcpCongestion:        c.TCPCongestion,
+		Interface:            c.Interface,
 	}, nil
 }