Parallel PGN result parser with minimal error handling

Measure-PGNResult.ps1

param(
    [parameter(Position=0)]
    $ChessFolder = 'D:\iisresetme\ChessData\'
)

# Prepare C# method to read and process the files
$Challenge = @{
    Name = 'ResultCounter' 
    Namespace = 'ChessData' 
    PassThru = $true
    UsingNamespace = @(
        'System.Collections',
        'System.Collections.Concurrent',
        'System.Collections.Generic',
        'System.IO',
        'System.Threading.Tasks'
    )
    MemberDefinition = @'
        public static Hashtable CountChessResults(string folder)
        {
            // Use a ConcurrentDictionary to avoid concurrent updates from Parallel.ForEach() overwriting each other
            ConcurrentDictionary<string, int> winners = new ConcurrentDictionary<string, int>(new Dictionary<string, int>() { { "Draw", 0 }, { "Black", 0 }, { "White", 0 } });
            Parallel.ForEach<string>(Directory.EnumerateFiles(folder, "*.pgn", SearchOption.AllDirectories), fileName =>
            {
                // StreamReader.ReadLine() seems to be the fastest text reader 
                using (StreamReader reader = new StreamReader(fileName))
                {
                    string line;
                    while ((line = reader.ReadLine()) != null)
                    {
                        if (line.StartsWith("[Result "))
                        {
                            if(line.Contains("1/2"))
                                winners.AddOrUpdate("Draw", 1, (k, v) => v + 1);
                            else if(line.Contains("1-0"))
                                winners.AddOrUpdate("Black", 1, (k, v) => v + 1);
                            else if(line.Contains("0-1"))
                                winners.AddOrUpdate("White", 1, (k, v) => v + 1);
                        }
                    }
                }
            });
            
            // return a hashtable, easily converted to an object in PowerShell
            return new Hashtable(winners);
        }
'@
}
$CompilerParams = [System.CodeDom.Compiler.CompilerParameters]::new()
$CompilerParams.CompilerOptions = "/optimize+ /warn:0"

# Don't try to re-add assembly if it already exists (ie. someone already ran the script once before)
try {
    $ChallengeModule = [ChessData.ResultCounter] -as [type]
}
catch{
    $ChallengeModule = Add-Type @Challenge -CompilerParameters $CompilerParams |Select-Object -First 1
}

# wrapper function that takes a path to the root folder containing *.pgn files
function Measure-PGNResult 
{ 
    param($path) 
    return New-Object psobject -Property $ChallengeModule::CountChessResults($(Resolve-Path $path).Path) 
}

Measure-Command {
    $Results = Measure-PGNResult $ChessFolder
}
$Results