C# Online Compiler | .NET Fiddle

using System; using System.Collections.Generic; using System.Text; 
using System.Diagnostics; 
					
public static class Program
{
	/// <summary>
	///  Human readable TimeStamp using modern Action delegate, leaving out zero parts and variable length placeholder formating 
	/// </summary>
	/// <param name="milliseconds">a long type</param>
	/// <returns>Human readable timespan string</returns>
	public static string HumanReadableTimeSpan(this long milliseconds)
	{
		if (milliseconds == 0) return "0 ms"; 

		StringBuilder sb = new StringBuilder(); 
		
		Action<int, StringBuilder, int> addActionToSB =  //or pass an entire new format!
		(val, displayunit, zeroplaces) => 
		{if (val > 0) 
			sb.AppendFormat(
					" {0:DZ}X".Replace("X", displayunit.ToString())
					.Replace("Z",zeroplaces.ToString())        
					,val
				); 
		};

		var t = TimeSpan.FromMilliseconds(milliseconds);

		//addActionToSBList(timespan property, readable display displayunit, number of zero placeholders) //Sun 24-Sep-17 8:30pm metadataconsulting.ca - Star Trek Disco
		addActionToSB(t.Days, new StringBuilder("d"),  1); 
		addActionToSB(t.Hours, new StringBuilder("h"), 2);
		addActionToSB(t.Minutes, new StringBuilder("m"), 2);
		addActionToSB(t.Seconds, new StringBuilder("s"), 2);
		addActionToSB(t.Milliseconds, new StringBuilder("ms"), 3); 
		
		return sb.ToString().TrimStart();
	}
	
	public static void Main()
	{
		 Stopwatch sw = new Stopwatch();
   		 Console.WriteLine("Human Readable TimeSpan"); 
		 sw.Start();
   		 string output = 111311234567L.HumanReadableTimeSpan();
   		 sw.Stop();
		 Console.WriteLine(output); 
		 Console.WriteLine(sw.ElapsedTicks+" ticks"); 
		
	}
}

 
using System; using System.Collections.Generic; using System.Text; 
using System.Diagnostics; 
                    
public static class Program
{
    /// <summary>
    ///  Human readable TimeStamp using modern Action delegate, leaving out zero parts and variable length placeholder formating 
    /// </summary>
    /// <param name="milliseconds">a long type</param>
    /// <returns>Human readable timespan string</returns>
    public static string HumanReadableTimeSpan(this long milliseconds)
    {
        if (milliseconds == 0) return "0 ms"; 
​
        StringBuilder sb = new StringBuilder(); 
        
        Action<int, StringBuilder, int> addActionToSB =  //or pass an entire new format!
        (val, displayunit, zeroplaces) => 
        {if (val > 0) 
            sb.AppendFormat(
                    " {0:DZ}X".Replace("X", displayunit.ToString())
                    .Replace("Z",zeroplaces.ToString())        
                    ,val
                ); 