Use the current EventLoop as the requests preferred EventLoop (#515)

* Use the current `EventLoop` as the requests prefered `EventLoop` if possible

* use released version of swift-nio

Author: dnadoba

Package.swift

@@ -21,7 +21,7 @@ let package = Package(
         .library(name: "AsyncHTTPClient", targets: ["AsyncHTTPClient"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.34.0"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.36.0"),
         .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.14.1"),
         .package(url: "https://github.com/apple/swift-nio-http2.git", from: "1.19.0"),
         .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.10.0"),

Sources/AsyncHTTPClient/HTTPClient.swift

@@ -545,7 +545,8 @@ public class HTTPClient {
         let taskEL: EventLoop
         switch eventLoopPreference.preference {
         case .indifferent:
-            taskEL = self.eventLoopGroup.next()
+            // if possible we want a connection on the current `EventLoop`
+            taskEL = self.eventLoopGroup.any()
         case .delegate(on: let eventLoop):
             precondition(self.eventLoopGroup.makeIterator().contains { $0 === eventLoop }, "Provided EventLoop must be part of clients EventLoopGroup.")
             taskEL = eventLoop