added DownloadFileAsync helpers

src/Client.cs

@@ -902,6 +902,48 @@ namespace WTelegram
 				return this.Messages_SendMedia(peer, media, text, Helpers.RandomLong(),
 					reply_to_msg_id: reply_to_msg_id, entities: entities, schedule_date: schedule_date);
 		}
+
+		/// <summary>Download given photo from Telegram into the outputStream</summary>
+		/// <param name="outputStream">stream to write to. This method does not close/dispose the stream</param>
+		/// <param name="photoSize">if unspecified, will download the largest version of the photo</param>
+		public async Task<Storage_FileType> DownloadFileAsync(Photo photo, Stream outputStream, PhotoSizeBase photoSize = null)
+		{
+			var fileLocation = photo.ToFileLocation(photoSize ?? photo.LargestPhotoSize);
+			await MigrateDCAsync(photo.dc_id);
+			return await DownloadFileAsync(fileLocation, outputStream);
+		}
+
+		/// <summary>Download given photo from Telegram into the outputStream</summary>
+		/// <param name="outputStream">stream to write to. This method does not close/dispose the stream</param>
+		/// <param name="thumbSize">if specified, will download the given thumbnail instead of the full document</param>
+		public async Task<Storage_FileType> DownloadFileAsync(Document document, Stream outputStream, PhotoSizeBase thumbSize = null)
+		{
+			var fileLocation = document.ToFileLocation(thumbSize);
+			await MigrateDCAsync(document.dc_id);
+			return await DownloadFileAsync(fileLocation, outputStream);
+		}
+
+		/// <summary>Download given file from Telegram into the outputStream</summary>
+		/// <param name="fileLocation">Telegram file identifier, typically obtained with a .ToFileLocation() call</param>
+		/// <param name="outputStream">stream to write to. This method does not close/dispose the stream</param>
+		public async Task<Storage_FileType> DownloadFileAsync(InputFileLocationBase fileLocation, Stream outputStream)
+		{
+			const int ChunkSize = 128 * 1024;
+			int fileSize = 0;
+			Upload_File fileData;
+			do
+			{
+				var fileBase = await this.Upload_GetFile(fileLocation, fileSize, ChunkSize);
+				fileData = fileBase as Upload_File;
+				if (fileData == null)
+					throw new ApplicationException("Upload_GetFile returned unsupported " + fileBase.GetType().Name);
+				await outputStream.WriteAsync(fileData.bytes, 0, fileData.bytes.Length);
+				fileSize += fileData.bytes.Length;
+				
+			} while (fileData.bytes.Length == ChunkSize);
+			await MigrateDCAsync(); // migrate back to main DC
+			return fileData.type;
+		}
 		#endregion
 
 		/// <summary>Enable the collection of id/access_hash pairs (experimental)</summary>

src/Generator.cs

@@ -337,6 +337,7 @@ namespace WTelegram
 		private void WriteTypeAsEnum(StreamWriter sw, TypeInfo typeInfo)
 		{
 			enumTypes.Add(typeInfo.ReturnName);
+			bool lowercase = typeInfo.ReturnName == "Storage_FileType";
 			sw.WriteLine($"{tabIndent}public enum {typeInfo.ReturnName} : uint");
 			sw.WriteLine($"{tabIndent}{{");
 			string prefix = "";
@@ -348,6 +349,7 @@ namespace WTelegram
 			{
 				string className = CSharpName(ctor.predicate);
 				if (!allTypes.Add(className)) continue;
+				if (lowercase) className = className.ToLowerInvariant();
 				ctorToTypes.Remove(ctor.ID);
 				sw.WriteLine($"{tabIndent}\t///<summary>See <a href=\"https://core.telegram.org/constructor/{ctor.predicate}\"/></summary>");
 				sw.WriteLine($"{tabIndent}\t{className[prefixLen..]} = 0x{ctor.ID:X8},");

src/TL.Schema.cs

@@ -413,25 +413,25 @@ namespace TL
 	public enum Storage_FileType : uint
 	{
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileUnknown"/></summary>
-		Unknown = 0xAA963B05,
+		unknown = 0xAA963B05,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.filePartial"/></summary>
-		Partial = 0x40BC6F52,
+		partial = 0x40BC6F52,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileJpeg"/></summary>
-		Jpeg = 0x007EFE0E,
+		jpeg = 0x007EFE0E,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileGif"/></summary>
-		Gif = 0xCAE1AADF,
+		gif = 0xCAE1AADF,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.filePng"/></summary>
-		Png = 0x0A4F63C0,
+		png = 0x0A4F63C0,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.filePdf"/></summary>
-		Pdf = 0xAE1E508D,
+		pdf = 0xAE1E508D,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileMp3"/></summary>
-		Mp3 = 0x528A0677,
+		mp3 = 0x528A0677,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileMov"/></summary>
-		Mov = 0x4B09EBBC,
+		mov = 0x4B09EBBC,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileMp4"/></summary>
-		Mp4 = 0xB3CEA0E4,
+		mp4 = 0xB3CEA0E4,
 		///<summary>See <a href="https://core.telegram.org/constructor/storage.fileWebp"/></summary>
-		Webp = 0x1081464C,
+		webp = 0x1081464C,
 	}
 
 	///<summary>See <a href="https://core.telegram.org/type/User"/></summary>