WebSocketException with Firefox

Hello,
I using Websocket-sharp for server. When connect with firefox, sometimes (randomly), show this error in server console, but work fine.

28-02-2018 22:46:27|Fatal|ExecutionContext.RunInternal|WebSocketSharp.WebSocketException: An exception has occurred while reading an HTTP request/response. ---> System.IO.EndOfStreamException: The header cannot be read from the data source.
                             en WebSocketSharp.HttpBase.<>c__DisplayClass1.<readHeaders>b__0(Int32 i)
                             en WebSocketSharp.Ext.EqualsWith(Int32 value, Char c, Action`1 action)
                             en WebSocketSharp.HttpBase.readHeaders(Stream stream, Int32 maxLength)
                             en WebSocketSharp.HttpBase.Read[T](Stream stream, Func`2 parser, Int32 millisecondsTimeout)
                             --- Fin del seguimiento de la pila de la excepción interna ---
                             en WebSocketSharp.HttpBase.Read[T](Stream stream, Func`2 parser, Int32 millisecondsTimeout)
                             en WebSocketSharp.HttpRequest.Read(Stream stream, Int32 millisecondsTimeout)
                             en WebSocketSharp.Net.WebSockets.TcpListenerWebSocketContext..ctor(TcpClient tcpClient, String protocol, Boolean secure, ServerSslConfiguration sslConfig, Logger logger)
                             en WebSocketSharp.Ext.GetWebSocketContext(TcpClient tcpClient, String protocol, Boolean secure, ServerSslConfiguration sslConfig, Logger logger)
                             en WebSocketSharp.Server.WebSocketServer.<>c__DisplayClass1.<receiveRequest>b__0(Object state)

If I connect with Chrome, this error dont show.

Start with WebSocketSharp.HttpBase.readHeaders and HttpRequest.Read, then trace how TcpListenerWebSocketContext handles the Firefox connection shown in the stack trace. Compare the failing Firefox request with the working Chrome path and determine whether the end-of-stream is handled correctly. Done means the intermittent Firefox connection no longer produces an inappropriate fatal server error.