The header of a frame cannot be read from the stream ?

hi , my problem is when i sent a long String , the error happened
like :|Fatal|<>c__DisplayClass17.<startReceiving>b__16|WebSocketSharp.WebSocketException: The header of a frame cannot be read from the stream. 於 WebSocketSharp.WebSocketFrame.processHeader(Byte[] header) 於 WebSocketSharp.WebSocketFrame.<>c__DisplayClassa.<readHeaderAsync>b__9(Byte[] bytes) 於 WebSocketSharp.Ext.<>c__DisplayClass9.<ReadBytesAsync>b__8(IAsyncResult ar) WebSocketSharp.CloseEventArgs
And i found someone had the problem too
like this
so i wonder know ,how can i solve this problem
and i try to set FragmentLength ,but i don't know how to do that
my Application is a Winsform client include websocketsharp.dll(on Nuget version 1.0.3-rc11)
and i try to sent long String to Stomp&SockJs Websocket Server
BTW,Sending short String is work , and i found the max length i can sent (Encoding.GetEncoding("utf-8").GetBytes ) it's 16546 , Any ideas?

Start with the stack-trace entry points WebSocketFrame.processHeader and readHeaderAsync, then review how the WebSocketSharp client handles the reported UTF-8 payload size near 16546 bytes. Reproduce the failure with short and long strings against the stated STOMP/SockJS server; done means the cause and supported handling of long messages are established.