Review code style to match with the existing code

Frameworks/MQTTnet.NetStandard/Internal/AsyncLock.cs

@@ -7,34 +7,42 @@ namespace MQTTnet.Internal
     // From Stephen Toub (https://blogs.msdn.microsoft.com/pfxteam/2012/02/12/building-async-coordination-primitives-part-6-asynclock/)
     public sealed class AsyncLock : IDisposable
     {
-        private readonly SemaphoreSlim m_semaphore = new SemaphoreSlim(1, 1);
-        private readonly Task<IDisposable> m_releaser;
+        private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
+        private readonly Task<IDisposable> _releaser;
 
         public AsyncLock()
         {
-            m_releaser = Task.FromResult((IDisposable)new Releaser(this));
+            _releaser = Task.FromResult((IDisposable)new Releaser(this));
         }
 
         public Task<IDisposable> LockAsync(CancellationToken cancellationToken)
         {
-            var wait = m_semaphore.WaitAsync(cancellationToken);
+            Task wait = _semaphore.WaitAsync(cancellationToken);
             return wait.IsCompleted ?
-                        m_releaser :
+                        _releaser :
                         wait.ContinueWith((_, state) => (IDisposable)state,
-                            m_releaser.Result, cancellationToken,
+                            _releaser.Result, cancellationToken,
                             TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
         }
 
         public void Dispose()
         {
-            this.m_semaphore?.Dispose();
+            _semaphore?.Dispose();
         }
 
         private sealed class Releaser : IDisposable
         {
-            private readonly AsyncLock m_toRelease;
-            internal Releaser(AsyncLock toRelease) { m_toRelease = toRelease; }
-            public void Dispose() { m_toRelease.m_semaphore.Release(); }
+            private readonly AsyncLock _toRelease;
+
+            internal Releaser(AsyncLock toRelease)
+            {
+                _toRelease = toRelease;
+            }
+
+            public void Dispose()
+            {
+                _toRelease._semaphore.Release();
+            }
         }
     }
 }