My $using implementation

## Scriptblock
$Data = 42
$Computername = $env:COMPUTERNAME
$ScriptBlock = {
    [pscustomobject]@{
        Output = (4 + $Using:Data * 2)
        Computername = $Using:Computername
    }
}

## Let's be quick and dirty and do a search and replace on the scriptblock
$usingVariables = $ScriptBlock.ast.FindAll({
    $args[0] -is [System.Management.Automation.Language.UsingExpressionAst]
},$True)

$List = New-Object 'System.Collections.Generic.List`1[System.Management.Automation.Language.VariableExpressionAst]'
$Params = New-Object System.Collections.ArrayList

If ($UsingVariables) {
    ForEach ($Ast in $UsingVariables) {
        [void]$list.Add($Ast.SubExpression)
    }
    [void]$Params.AddRange(($UsingVariableData.NewName | Select -Unique))
    $NewParams = $Params -join ', '
    $Tuple=[Tuple]::Create($list,$NewParams)

    $bindingFlags = [Reflection.BindingFlags]"Default,NonPublic,Instance"
    $GetWithInputHandlingForInvokeCommandImpl = ($ScriptBlock.ast.gettype().GetMethod('GetWithInputHandlingForInvokeCommandImpl',$bindingFlags))
    $StringScriptBlock = $GetWithInputHandlingForInvokeCommandImpl.Invoke($ScriptBlock.ast,@($Tuple))
    $ScriptBlock = [scriptblock]::Create($StringScriptBlock)
}

$serializedVariables = foreach($variable in $list) {
    [pscustomobject]@{
        Name = '__using_' + $variable.VariablePath.UserPath
        SerializedValue = [System.Management.Automation.PSSerializer]::Serialize(
            (Get-Variable -Name $variable.VariablePath.UserPath).Value
        )
    }
}

foreach($serializedVariable in $serializedVariables) {
    Set-Variable -Name $serializedVariable.Name -Value (
        [System.Management.Automation.PSSerializer]::Deserialize($serializedVariable.SerializedValue)
    )
}
$ScriptBlock
. $ScriptBlock