C# download file from url validate file type .zip

AAC audioAbiWord documentArchive document (multiple files embedded)AVI: Audio Video InterleaveAmazon Kindle eBook formatAny kind of binary dataWindows OS/2 Bitmap GraphicsBZip archiveBZip2 archiveC-Shell scriptCascading Style Sheets (CSS)Comma-separated values (CSV)Microsoft WordMicrosoft Word (OpenXML)MS Embedded OpenType fontsElectronic publication (EPUB)GZip Compressed ArchiveGraphics Interchange Format (GIF)HyperText Markup Language (HTML)Icon formatiCalendar formatJava Archive (JAR)
JPEG imagesJavaScript

, per the following specifications:

JSON formatJSON-LD format
Musical Instrument Digital Interface (MIDI)JavaScript moduleMP3 audioMPEG VideoApple Installer PackageOpenDocument presentation documentOpenDocument spreadsheet documentOpenDocument text documentOGG audioOGG videoOGGOpus audioOpenType fontPortable Network GraphicsAdobe Portable Document Format (PDF)Hypertext Preprocessor (Personal Home Page)Microsoft PowerPointMicrosoft PowerPoint (OpenXML)RAR archiveRich Text Format (RTF)Bourne shell scriptScalable Vector Graphics (SVG)Small web format (SWF) or Adobe Flash documentTape Archive (TAR)Tagged Image File Format (TIFF)MPEG transport streamTrueType FontText, (generally ASCII or ISO n)Microsoft VisioWaveform Audio FormatWEBM audioWEBM videoWEBP imageWeb Open Font Format (WOFF)Web Open Font Format (WOFF)XHTMLMicrosoft ExcelMicrosoft Excel (OpenXML)if not readable from casual users (RFC , section 3)
if readable from casual users (RFC , section 3)XULZIP archive3GPP audio/video container
if it doesn't contain video3GPP2 audio/video container
if it doesn't contain video7-zip archive