winutil/functions/private/Save-WinUtilFile.ps1

function Save-WinUtilFile {
    <#
    .SYNOPSIS
        Downloads a file and reports transfer progress.
    #>
    param(
        [Parameter(Mandatory)]
        [uri]$Uri,

        [Parameter(Mandatory)]
        [string]$DestinationPath,

        [Parameter(Mandatory)]
        [scriptblock]$ProgressCallback
    )

    $response = $null
    $responseStream = $null
    $outputStream = $null

    try {
        $request = [System.Net.WebRequest]::Create($Uri)
        $response = $request.GetResponse()
        $totalBytes = $response.ContentLength
        $responseStream = $response.GetResponseStream()
        $outputStream = [System.IO.File]::Create($DestinationPath)
        $buffer = New-Object byte[] 81920
        $downloadedBytes = 0L
        $lastPercent = -1

        while (($bytesRead = $responseStream.Read($buffer, 0, $buffer.Length)) -gt 0) {
            $outputStream.Write($buffer, 0, $bytesRead)
            $downloadedBytes += $bytesRead

            if ($totalBytes -gt 0) {
                $percent = [Math]::Min(100, [int](($downloadedBytes / $totalBytes) * 100))
                if ($percent -ne $lastPercent) {
                    & $ProgressCallback $percent
                    $lastPercent = $percent
                }
            }
        }

        if ($lastPercent -ne 100) {
            & $ProgressCallback 100
        }
    }
    finally {
        if ($null -ne $outputStream) {
            $outputStream.Dispose()
        }
        if ($null -ne $responseStream) {
            $responseStream.Dispose()
        }
        if ($null -ne $response) {
            $response.Dispose()
        }
    }
}