Started work on h2

Author: fabianfett

Diff for: Package.swift

@@ -22,6 +22,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.27.0"),
+        .package(url: "https://github.com/apple/swift-nio-http2.git", from: "1.7.0"),
         .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.13.0"),
         .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.3.0"),
         .package(url: "https://github.com/apple/swift-nio-transport-services.git", from: "1.5.1"),
@@ -30,7 +31,7 @@ let package = Package(
     targets: [
         .target(
             name: "AsyncHTTPClient",
-            dependencies: ["NIO", "NIOHTTP1", "NIOSSL", "NIOConcurrencyHelpers", "NIOHTTPCompression",
+            dependencies: ["NIO", "NIOHTTP1", "NIOHTTP2", "NIOSSL", "NIOConcurrencyHelpers", "NIOHTTPCompression",
                            "NIOFoundationCompat", "NIOTransportServices", "Logging"]
         ),
         .testTarget(

Diff for: Sources/AsyncHTTPClient/ConnectionPool/HTTPConnectionEvents.swift

@@ -0,0 +1,17 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the AsyncHTTPClient open source project
+//
+// Copyright (c) 2021 Apple Inc. and the AsyncHTTPClient project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+enum HTTPConnectionEvent {
+    case cancelRequest
+}

Diff for: Sources/AsyncHTTPClient/ConnectionPool/HTTPConnectionPool+Factory.swift

@@ -46,6 +46,58 @@ extension HTTPConnectionPool {
 }
 
 extension HTTPConnectionPool.ConnectionFactory {
+    
+    func makeConnection(for pool: HTTPConnectionPool, connectionID: HTTPConnectionPool.Connection.ID, eventLoop: EventLoop, logger: Logger) {
+        var logger = logger
+        logger[metadataKey: "ahc-connection"] = "\(connectionID)"
+
+        let future: EventLoopFuture<(Channel, HTTPVersion)>
+
+        if self.key.scheme.isProxyable, let proxy = self.clientConfiguration.proxy {
+            future = self.makeHTTPProxyChannel(proxy, connectionID: connectionID, eventLoop: eventLoop, logger: logger)
+        } else {
+            future = self.makeChannel(eventLoop: eventLoop, logger: logger)
+        }
+
+        future.whenComplete { result in
+            do {
+                switch result {
+                case .success(let (channel, .http1_0)), .success(let (channel, .http1_1)):
+                    let connection = try HTTP1Connection(
+                        channel: channel,
+                        connectionID: connectionID,
+                        configuration: self.clientConfiguration,
+                        delegate: pool,
+                        logger: logger
+                    )
+                    pool.http1ConnectionCreated(connection)
+                case .success(let (channel, .http2)):
+                    let http2Connection = try HTTP2Connection(
+                        channel: channel,
+                        connectionID: connectionID,
+                        delegate: pool,
+                        logger: logger
+                    )
+
+                    http2Connection.readyToAcceptConnectionsFuture.whenComplete { result in
+                        switch result {
+                        case .success:
+                            pool.http2ConnectionCreated(http2Connection)
+                        case .failure(let error):
+                            pool.failedToCreateHTTPConnection(connectionID, error: error)
+                        }
+                    }
+                case .failure(let error):
+                    throw error
+                default:
+                    preconditionFailure("Unexpected new http version")
+                }
+            } catch {
+                pool.failedToCreateHTTPConnection(connectionID, error: error)
+            }
+        }
+    }
+    
     func makeBestChannel(connectionID: HTTPConnectionPool.Connection.ID, eventLoop: EventLoop, logger: Logger) -> EventLoopFuture<(Channel, HTTPVersion)> {
         if self.key.scheme.isProxyable, let proxy = self.clientConfiguration.proxy {
             return self.makeHTTPProxyChannel(proxy, connectionID: connectionID, eventLoop: eventLoop, logger: logger)