Package Socket:

- fix tcp,udp,unix socket
- add socket unixgram for session less unix socket
- optmize process & code
- add some standalone test for server / client (add example server config for
  rsyslog)

Package Network/Protocol:
- add unixgram protocol

Package Errors:
- fix bug in loop to prevent circular include

network/protocol/interface.go

@@ -46,6 +46,7 @@ const (
 	NetworkIP
 	NetworkIP4
 	NetworkIP6
+	NetworkUnixGram
 )
 
 func Parse(str string) NetworkProtocol {
@@ -60,6 +61,8 @@ func Parse(str string) NetworkProtocol {
 		return NetworkUDP
 	case strings.EqualFold(NetworkUnix.Code(), str):
 		return NetworkUnix
+	case strings.EqualFold(NetworkUnixGram.Code(), str):
+		return NetworkUnixGram
 	default:
 		return NetworkEmpty
 	}