fix(OSS-1010): Set Keep-Alive timeout to 3 seconds (#177)

Author: parkhomenko

FaunaDB.Client/Client/DefaultClientIO.cs

@@ -97,6 +97,11 @@ private async Task<RequestResult> DoRequestAsync(HttpMethodKind method, string p
             message.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
             message.Headers.Add("X-FaunaDB-API-Version", "4");
             message.Headers.Add("X-Driver-Env", RuntimeEnvironmentHeader.Construct(EnvironmentEditor.Create()));
+            if (httpVersion.ToString() == "1.1")
+            {
+                message.Headers.Add("Keep-Alive", "3000");
+            }
+
             message.Version = httpVersion;
 
             // adding custom headers provided during the client creation