Thread-safely write to files in C#

StringExtensions.cs

using System.IO;
using System.Threading;

namespace Util
{
	/// <summary>
	/// Various extensions to the String class.
	/// </summary>
	public static class StringExtensions
	{
		/// <summary>
		/// Writes to a file in a thread-safe manner using a Mutex lock.
		/// Overwrites files by default.
		/// </summary>
		/// <remarks>Inspired by https://stackoverflow.com/a/229567 .</remarks>
		/// <param name="output">Input string to write to the file.</param>
		/// <param name="filePath">Path of file to write to.</param>
		/// <param name="overwrite">Whether to overwrite pre-existing files.</param>
		public static void SafelyWriteToFile( this string output, string filePath, bool overwrite = true )
		{

			// Unique id for global mutex - Global prefix means it is global to the machine
			// We use filePath to ensure the mutex is only held for the particular file
			string mutexId = string.Format( "Global\\{{{0}}}", Path.GetFileNameWithoutExtension( filePath ) );

			// We create/query the Mutex
			using ( var mutex = new Mutex( false, mutexId ) ) {

				var hasHandle = false;

				try {

					// We wait for lock to release
					hasHandle = mutex.WaitOne( Timeout.Infinite, false );

					// Write to file
					if ( overwrite )
						File.WriteAllText( filePath, output );
					else
						File.AppendAllText( filePath, output );

				} finally {

					// If we have the Mutex, we release it
					if ( hasHandle )
						mutex.ReleaseMutex();
				}
			}
		}
	}
}