Replace usage of Split-Path to improve performance

[IMJLA]

# Here is the prep code.  We're going to prep some fake test data instead down below
$DirectoryPath = 'WinNT://Sample-TestPC/Authenticated Users'

# Here we will list the various methods whose performance we want to test:
$Scriptblocks = @(
    { 
        # Here is the prep code we will use to generate fake test data.100k fake servers, and 10k fake serial numbers to lookup.
        $n = 100000
        Write-Host "Looping $n times..."
        $Servers = for ($i = 0; $i -lt $n; $i++) {
            $Length = $DirectoryPath.LastIndexOf('/')
            $DirectoryPath.Substring(0,$Length)
        }
    },


    {
        # Here is the prep code we will use to generate fake test data.100k fake servers, and 10k fake serial numbers to lookup.
        $n = 100000
        Write-Host "Looping $n times..."
        $Servers = for ($i = 0; $i -lt $n; $i++) {
            $DirectoryPath | Split-Path -Parent
        }
    }
)


# Here is our function to test the performance of each method
Function Test-ScriptBlockPerformance {
    param (
        [Parameter(ValueFromPipeline)]
        [scriptblock[]]$ScriptBlock
    )
    process {
        ForEach ($ThisScript in $ScriptBlock) {
            Write-Host "Starting test of expression {$ThisScript}"
            $Result = Measure-Command -Expression $ThisScript
            [pscustomobject]@{
                Expression = "{$ThisScript}"
                Result = $Result
                Ticks = $Result.Ticks
            }
        }
    }
}


# Here is where we invoke our function to run the performance tests, and sort the results to find a winner (the fastest method)
$Leaderboard = $Scriptblocks | Test-ScriptBlockPerformance | Sort-Object -Property Ticks
$Leaderboard | Format-Table Ticks,Expression -AutoSize

Expected Behavior

Code is similar to the second sample code completes in only 3873692 tickets (~69% reduction)

Current Behavior

Export-Permission and dependencies contain code similar to the first sample code which completes in 123239274 ticks

Possible Solution

Replace Split-Path with .Net string manipulation methods