Reimplement UploadBuffer to use 64K blocks
Reimplement UploadBuffer to use 64K blocks

jskeet/google-api-dotnet-client,googleapis/google-api-dotnet-client,googleapis/google-api-dotnet-client,jskeet/google-api-dotnet-client,googleapis/google-api-dotnet-client,jskeet/google-api-dotnet-client