--- a/Implab/PromiseHandler.cs	Tue Jan 30 01:37:17 2018 +0300
+++ b/Implab/PromiseHandler.cs	Wed Jan 31 11:28:38 2018 +0300
@@ -3,10 +3,10 @@
 
 namespace Implab {
     class PromiseHandler {
-        public static Action<T> Create<T>(Action<T> handler, Deferred next) {
+        public static Action<T, Deferred> Create<T>(Action<T> handler) {
             Debug.Assert(handler != null);
 
-            return (v) => {
+            return (v, next) => {
                 try {
                     handler(v);
                     next.Resolve();
@@ -16,10 +16,10 @@
             };
         }
 
-        public static Action<T> Create<T>(Func<T, IPromise> handler, Deferred next) {
+        public static Action<T, Deferred> Create<T>(Func<T, IPromise> handler) {
             Debug.Assert(handler != null);
 
-            return (v) => {
+            return (v, next) => {
                 try {
                     next.Resolve(handler(v));
                 } catch (Exception err) {
@@ -28,10 +28,10 @@
             };
         }
 
-        public static Action<T> Create<T, T2>(Func<T, T2> handler, Deferred<T2> next) {
+        public static Action<T, Deferred<T2>> Create<T, T2>(Func<T, T2> handler) {
             Debug.Assert(handler != null);
 
-            return (v) => {
+            return (v, next) => {
                 try {
                     next.Resolve(handler(v));
                 } catch (Exception err) {
@@ -40,9 +40,9 @@
             };
         }
 
-        public static Action<T> Create<T, T2>(Func<T, IPromise<T2>> handler, Deferred<T2> next) {
+        public static Action<T, Deferred<T2>> Create<T, T2>(Func<T, IPromise<T2>> handler) {
             Debug.Assert(handler != null);
-            return (v) => {
+            return (v, next) => {
                 try {
                     next.Resolve(handler(v));
                 } catch (Exception err) {
@@ -51,10 +51,10 @@
             };
         }
 
-        public static Action Create(Action handler, Deferred next) {
+        public static Action<Deferred> Create(Action handler) {
             Debug.Assert(handler != null);
 
-            return () => {
+            return (next) => {
                 try {
                     handler();
                     next.Resolve();
@@ -64,10 +64,10 @@
             };
         }
 
-        public static Action Create(Func<IPromise> handler, Deferred next) {
+        public static Action<Deferred> Create(Func<IPromise> handler) {
             Debug.Assert(handler != null);
 
-            return () => {
+            return (next) => {
                 try {
                     next.Resolve(handler());
                 } catch (Exception err) {
@@ -76,10 +76,10 @@
             };
         }
 
-        public static Action Create<T2>(Func<T2> handler, Deferred<T2> next) {
+        public static Action<Deferred<T2>> Create<T2>(Func<T2> handler) {
             Debug.Assert(handler != null);
 
-            return () => {
+            return (next) => {
                 try {
                     next.Resolve(handler());
                 } catch (Exception err) {
@@ -88,9 +88,9 @@
             };
         }
 
-        public static Action Create<T2>(Func<IPromise<T2>> handler, Deferred<T2> next) {
+        public static Action<Deferred<T2>> Create<T2>(Func<IPromise<T2>> handler) {
             Debug.Assert(handler != null);
-            return () => {
+            return (next) => {
                 try {
                     next.Resolve(handler());
                 } catch (Exception err) {