Use async FileStreams where it makes sense

MediaBrowser.Model/IO/AsyncFile.cs

@@ -0,0 +1,34 @@
+using System;
+using System.IO;
+
+namespace MediaBrowser.Model.IO
+{
+    /// <summary>
+    /// Helper class to create async <see cref="FileStream" />s.
+    /// </summary>
+    public static class AsyncFile
+    {
+        /// <summary>
+        /// Gets a value indicating whether we should use async IO on this platform.
+        /// <see href="https://github.com/dotnet/runtime/issues/16354" />.
+        /// </summary>
+        /// <returns>Returns <c>false</c> on Windows; otherwise <c>true</c>.</returns>
+        public static bool UseAsyncIO => !OperatingSystem.IsWindows();
+
+        /// <summary>
+        /// Opens an existing file for reading.
+        /// </summary>
+        /// <param name="path">The file to be opened for reading.</param>
+        /// <returns>A read-only <see cref="FileStream" /> on the specified path.</returns>
+        public static FileStream OpenRead(string path)
+            => new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, IODefaults.FileStreamBufferSize, UseAsyncIO);
+
+        /// <summary>
+        /// Opens an existing file for writing.
+        /// </summary>
+        /// <param name="path">The file to be opened for writing.</param>
+        /// <returns>An unshared <see cref="FileStream" /> object on the specified path with Write access.</returns>
+        public static FileStream OpenWrite(string path)
+            => new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None, IODefaults.FileStreamBufferSize, UseAsyncIO);
+    }
+}