Created attachment 18554 [details]
When using chunked encoding in response, then writing zero buffer to output Stream will result
writing Chunk End Mark to client ("0\r\n"). This happens because count argument of ResponseStream class in Write method (https://github.com/mono/mono/blob/master/mcs/class/System/System.Net/ResponseStream.cs) is tested for zero after chunk prefix is writed to lower stream.
I tested this case in MS.NET, it worked well.
I attach code sample to reproduce this and also I have a pcap dump of wrong respose.
Created attachment 18555 [details]
Fixed in master