As for interface casting

Co-authored-by: Gorbunov Kirill Andreevich <kgorbunov@mtsbank.ru>
Reviewed-on: #299
Co-authored-by: Кирилл Горбунов <kirya_gorbunov_2015@mail.ru>
Co-committed-by: Кирилл Горбунов <kirya_gorbunov_2015@mail.ru>

micro.go

@@ -0,0 +1,94 @@
+package micro
+
+import (
+	"reflect"
+
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/flow"
+	"go.unistack.org/micro/v3/fsm"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/resolver"
+	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/server"
+	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v3/sync"
+	"go.unistack.org/micro/v3/tracer"
+)
+
+func As(b any, target any) bool {
+	if b == nil {
+		return false
+	}
+	if target == nil {
+		return false
+	}
+	val := reflect.ValueOf(target)
+	typ := val.Type()
+	if typ.Kind() != reflect.Ptr || val.IsNil() {
+		return false
+	}
+	targetType := typ.Elem()
+	if targetType.Kind() != reflect.Interface {
+		switch {
+		case targetType.Implements(brokerType):
+			break
+		case targetType.Implements(loggerType):
+			break
+		case targetType.Implements(clientType):
+			break
+		case targetType.Implements(serverType):
+			break
+		case targetType.Implements(codecType):
+			break
+		case targetType.Implements(flowType):
+			break
+		case targetType.Implements(fsmType):
+			break
+		case targetType.Implements(meterType):
+			break
+		case targetType.Implements(registerType):
+			break
+		case targetType.Implements(resolverType):
+			break
+		case targetType.Implements(selectorType):
+			break
+		case targetType.Implements(storeType):
+			break
+		case targetType.Implements(syncType):
+			break
+		case targetType.Implements(serviceType):
+			break
+		case targetType.Implements(routerType):
+			break
+		default:
+			return false
+		}
+	}
+	if reflect.TypeOf(b).AssignableTo(targetType) {
+		val.Elem().Set(reflect.ValueOf(b))
+		return true
+	}
+	return false
+}
+
+var brokerType = reflect.TypeOf((*broker.Broker)(nil)).Elem()
+var loggerType = reflect.TypeOf((*logger.Logger)(nil)).Elem()
+var clientType = reflect.TypeOf((*client.Client)(nil)).Elem()
+var serverType = reflect.TypeOf((*server.Server)(nil)).Elem()
+var codecType = reflect.TypeOf((*codec.Codec)(nil)).Elem()
+var flowType = reflect.TypeOf((*flow.Flow)(nil)).Elem()
+var fsmType = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
+var meterType = reflect.TypeOf((*meter.Meter)(nil)).Elem()
+var registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
+var resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
+var routerType = reflect.TypeOf((*router.Router)(nil)).Elem()
+var selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
+var storeType = reflect.TypeOf((*store.Store)(nil)).Elem()
+var syncType = reflect.TypeOf((*sync.Sync)(nil)).Elem()
+var tracerType = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
+var serviceType = reflect.TypeOf((*Service)(nil)).Elem()