Add logging of requests and the encryption key.

BulkPrintingAPI/appsettings.Development.json

     "Host": "41.223.25.5",
     "Port": 4006,
     "ConnectTimeout": 10000,
-    "ReceiveTimeout": 10000,
+    "ReceiveTimeout": 60000,
     "SendTimeout": 10000,
     "LogResponses":  true
   }

MAXClient/Client.cs

             // Key exchange
             _des = TripleDES.Create();
             _des.IV = new byte[8];
+            if (_logResponses)
+            {
+                _logger.LogDebug("Key for {0}: {1}",
+                    LoginCredentials.Format(_userId, _username, _vendorId, _serialNumber),
+                    BitConverter.ToString(_des.Key).Replace("-", "")
+                );
+            }
             await WriteMessageAsync(new MessageBuilder()
                 .Append("3D ")
                 .Append(EncryptRSA(response, BitConverter.ToString(_des.Key).Replace("-", "")))).ConfigureAwait(false);
         private async Task WriteMessageAsync(MessageBuilder message)
         {
             byte[] data = message.GetBytes();
+            if (_logResponses)
+            {
+                _logger.LogDebug("Request for {0}: {1}",
+                    LoginCredentials.Format(_userId, _username, _vendorId, _serialNumber),
+                    Encoding.ASCII.GetString(data, 2, data.Length - 2)
+                );
+            }
             await _connectionStream.WriteAsync(data, 0, data.Length).ConfigureAwait(false);
         }
     }