Replace Lock with NIOLock (#157)

Motivation:

Lock has been deprecated in favour of NIOLock. Warnings aren't great.

Modifications:

- Replace Lock with NIOLock
- Update the minimum required NIO version to 2.42.0.

Result:

Everything builds cleanly

Package.swift

@@ -21,7 +21,7 @@ let package = Package(
         .library(name: "NIOTransportServices", targets: ["NIOTransportServices"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.41.1"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.42.0"),
         .package(url: "https://github.com/apple/swift-atomics.git", from: "1.0.2"),
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
     ],

Package@swift-5.4.swift

@@ -21,7 +21,7 @@ let package = Package(
         .library(name: "NIOTransportServices", targets: ["NIOTransportServices"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.32.0"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.42.0"),
         .package(url: "https://github.com/apple/swift-atomics.git", from: "1.0.2"),
     ],
     targets: [

Package@swift-5.5.swift

@@ -21,7 +21,7 @@ let package = Package(
         .library(name: "NIOTransportServices", targets: ["NIOTransportServices"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.32.0"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.42.0"),
         .package(url: "https://github.com/apple/swift-atomics.git", from: "1.0.2"),
     ],
     targets: [

Sources/NIOTransportServices/NIOTSConnectionChannel.swift

@@ -204,7 +204,7 @@ internal final class NIOTSConnectionChannel {
     private var _addressCache = AddressCache(local: nil, remote: nil)
 
     /// A lock that guards the _addressCache.
-    private let _addressCacheLock = Lock()
+    private let _addressCacheLock = NIOLock()
 
     /// Create a `NIOTSConnectionChannel` on a given `NIOTSEventLoop`.
     ///

Sources/NIOTransportServices/NIOTSListenerChannel.swift

@@ -101,7 +101,7 @@ internal final class NIOTSListenerChannel {
     private var _addressCache = AddressCache(local: nil, remote: nil)
 
     /// A lock that guards the _addressCache.
-    private let _addressCacheLock = Lock()
+    private let _addressCacheLock = NIOLock()
 
 
     /// Create a `NIOTSListenerChannel` on a given `NIOTSEventLoop`.

Tests/NIOTransportServicesTests/NIOTSBootstrapTests.swift

@@ -25,7 +25,7 @@ import Foundation
 @available(OSX 10.14, iOS 12.0, tvOS 12.0, *)
 final class NIOTSBootstrapTests: XCTestCase {
     var groupBag: [NIOTSEventLoopGroup]? = nil // protected by `self.lock`
-    let lock = Lock()
+    let lock = NIOLock()
 
     override func setUp() {
         self.lock.withLock {