From b8721a1596ce0ff63a3a0f12d0f1130c52068700 Mon Sep 17 00:00:00 2001
From: Artem Redkin <aredkin@apple.com>
Date: Mon, 23 Sep 2019 15:52:30 +0100
Subject: [PATCH 1/3] cancel should be done with outbound user event

---
 Sources/AsyncHTTPClient/HTTPHandler.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/AsyncHTTPClient/HTTPHandler.swift b/Sources/AsyncHTTPClient/HTTPHandler.swift
index d4abc8d84..416a30ecf 100644
--- a/Sources/AsyncHTTPClient/HTTPHandler.swift
+++ b/Sources/AsyncHTTPClient/HTTPHandler.swift
@@ -476,7 +476,7 @@ extension HTTPClient {
             self.lock.withLock {
                 if !cancelled {
                     cancelled = true
-                    channel?.pipeline.fireUserInboundEventTriggered(TaskCancelEvent())
+                    channel?.triggerUserOutboundEvent(TaskCancelEvent(), promise: nil)
                 }
             }
         }

From dea199849db95c963b890a4f9a11bb8620ca3ed3 Mon Sep 17 00:00:00 2001
From: Artem Redkin <aredkin@apple.com>
Date: Mon, 23 Sep 2019 16:09:32 +0100
Subject: [PATCH 2/3] review fix: fire event out of the lock

---
 Sources/AsyncHTTPClient/HTTPHandler.swift | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Sources/AsyncHTTPClient/HTTPHandler.swift b/Sources/AsyncHTTPClient/HTTPHandler.swift
index 416a30ecf..45548fa7d 100644
--- a/Sources/AsyncHTTPClient/HTTPHandler.swift
+++ b/Sources/AsyncHTTPClient/HTTPHandler.swift
@@ -473,12 +473,14 @@ extension HTTPClient {
 
         /// Cancels the request execution.
         public func cancel() {
-            self.lock.withLock {
+            let channel: Channel? = self.lock.withLock {
                 if !cancelled {
                     cancelled = true
-                    channel?.triggerUserOutboundEvent(TaskCancelEvent(), promise: nil)
+                    return self.channel
                 }
+                return nil
             }
+            channel?.triggerUserOutboundEvent(TaskCancelEvent(), promise: nil)
         }
 
         @discardableResult

From 77e1ea1a4da5f40c8030830bd629f4b2aaaf7096 Mon Sep 17 00:00:00 2001
From: Artem Redkin <aredkin@apple.com>
Date: Mon, 23 Sep 2019 16:26:21 +0100
Subject: [PATCH 3/3] test fix: handle outbound events

---
 Sources/AsyncHTTPClient/HTTPHandler.swift | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/Sources/AsyncHTTPClient/HTTPHandler.swift b/Sources/AsyncHTTPClient/HTTPHandler.swift
index 45548fa7d..3913389a1 100644
--- a/Sources/AsyncHTTPClient/HTTPHandler.swift
+++ b/Sources/AsyncHTTPClient/HTTPHandler.swift
@@ -734,12 +734,19 @@ extension TaskHandler: ChannelDuplexHandler {
             self.state = .end
             let error = HTTPClientError.readTimeout
             self.failTaskAndNotifyDelegate(error: error, self.delegate.didReceiveError)
-        } else if (event as? TaskCancelEvent) != nil {
+        } else {
+            context.fireUserInboundEventTriggered(event)
+        }
+    }
+
+    func triggerUserOutboundEvent(context: ChannelHandlerContext, event: Any, promise: EventLoopPromise<Void>?) {
+        if (event as? TaskCancelEvent) != nil {
             self.state = .end
             let error = HTTPClientError.cancelled
             self.failTaskAndNotifyDelegate(error: error, self.delegate.didReceiveError)
+            promise?.succeed(())
         } else {
-            context.fireUserInboundEventTriggered(event)
+            context.triggerUserOutboundEvent(event, promise: promise)
         }
     }