Counting files example

CountFiles.cs

public static int CountFiles(string directory, bool recursive)
{
    return (new FileSystemEnumerable<int>(
        directory,
        (ref FileSystemEntry entry) => 1,
        new EnumerationOptions() { RecurseSubdirectories = recursive })
    {
        ShouldIncludePredicate = (ref FileSystemEntry entry) => !entry.IsDirectory
    }).Count();
}