Fix exception using chunked uploading with small files

DropboxClientExtensions.cs

@@ -9,6 +9,9 @@ namespace PneumaticTube
 {
 	internal static class DropboxClientExtensions
 	{
+		public const int ChunkSize = 128 * 1024;
+		public const int ChunkedThreshold = 150 * 1024 * 1024;
+
 		private static string CombinePath(string folder, string fileName) 
 		{
 			// We can't use Path.Combine here because we'll end up with the Windows separator ("\") and 
@@ -32,10 +35,9 @@ public static async Task<FileMetadata> Upload(this DropboxClient client, string
 		public static async Task<FileMetadata> UploadChunked(this DropboxClient client, 
 			string folder, string fileName, Stream fs, CancellationToken cancellationToken, IProgress<long> progress)
 		{
-			const int chunkSize = 128 * 1024;
-			int chunks = (int)Math.Ceiling((double)fs.Length / chunkSize);
+			int chunks = (int)Math.Ceiling((double)fs.Length / ChunkSize);
 
-			byte[] buffer = new byte[chunkSize];
+			byte[] buffer = new byte[ChunkSize];
 			string sessionId = null;
 
 			FileMetadata resultMetadata = null;
@@ -48,9 +50,9 @@ public static async Task<FileMetadata> UploadChunked(this DropboxClient client,
 					throw new OperationCanceledException(cancellationToken);
 				}
 
-				var byteRead = fs.Read(buffer, 0, chunkSize);
+				var bytesRead = fs.Read(buffer, 0, ChunkSize);
 
-				using(var memStream = new MemoryStream(buffer, 0, byteRead))
+				using(var memStream = new MemoryStream(buffer, 0, bytesRead))
 				{
 					if(i == 0)
 					{
@@ -59,7 +61,7 @@ public static async Task<FileMetadata> UploadChunked(this DropboxClient client,
 					}
 					else
 					{
-						UploadSessionCursor cursor = new UploadSessionCursor(sessionId, (ulong)(chunkSize * i));
+						UploadSessionCursor cursor = new UploadSessionCursor(sessionId, (ulong)(ChunkSize * i));
 
 						if(i == chunks - 1)
 						{
@@ -75,7 +77,7 @@ public static async Task<FileMetadata> UploadChunked(this DropboxClient client,
 							await client.Files.UploadSessionAppendV2Async(cursor, body: memStream);
 							if(!cancellationToken.IsCancellationRequested)
 							{
-								progress.Report(i * chunkSize);
+								progress.Report(i * ChunkSize);
 							}
 						}
 					}

Program.cs

@@ -104,8 +104,6 @@ private static int Main(string[] args)
             return (int)exitCode;
         }
 
-
-
 	    private static async Task Upload(IEnumerable<string> paths, UploadOptions options, DropboxClient client,
             CancellationToken cancellationToken)
         {
@@ -134,12 +132,18 @@ private static async Task Upload(string source, string filename, UploadOptions o
             {
                 Metadata uploaded;
 
-				if(!options.Chunked && fs.Length >= 150 * 1024 * 1024)
+				if(!options.Chunked && fs.Length >= DropboxClientExtensions.ChunkedThreshold)
 				{
 					Output("File is larger than 150MB, using chunked uploading.", options);
 					options.Chunked = true;
 				}
 
+                if (options.Chunked && fs.Length <= DropboxClientExtensions.ChunkSize) 
+                {
+                    Output("File is less than 128kB, disabling chunked uploading.", options);
+                    options.Chunked = false;
+                }
+
 				if(options.Chunked)
 				{
 					var progress = ConfigureProgressHandler(options, fs.Length);