It is possible to notice if Graylog connection is lost.

Source/EasyGelf.Core/SilentLogger.cs

@@ -6,16 +6,34 @@ public interface IEasyGelfLogger
     {
         void Error(string message, Exception exception);
         void Debug(string message);
+        void SetException(Exception e);
+        void CheckException();
     }
 
     public sealed class SilentLogger : IEasyGelfLogger
     {
+        private static Exception threadException = null;
+
         public void Error(string message, Exception exception)
         {
         }
 
         public void Debug(string message)
         {
         }
+
+        public void SetException(Exception exception)
+        {
+            threadException = exception;
+        }
+        public void CheckException()
+        {
+            Exception e = threadException;
+            if (threadException != null)
+            {
+                threadException = null;
+                throw e;
+            }
+        }
     }
 }

Source/EasyGelf.Core/Transports/BufferedTransport.cs

@@ -27,6 +27,7 @@ public BufferedTransport(IEasyGelfLogger logger, ITransport transport)
                             catch(Exception exception)
                             {
                                 logger.Error("Cannot send message", exception);
+                                logger.SetException(exception);
                             }
                         }
                     }
@@ -42,6 +43,7 @@ public BufferedTransport(IEasyGelfLogger logger, ITransport transport)
                             catch (Exception exception)
                             {
                                 logger.Error("Cannot send message", exception);
+                                logger.SetException(exception);
                             }
                         }
                     }

Source/EasyGelf.Log4Net/VerboseLogger.cs

@@ -6,6 +6,7 @@ namespace EasyGelf.Log4Net
 {
     public sealed class VerboseLogger : IEasyGelfLogger
     {
+        private static Exception threadException = null;
         public void Error(string message, Exception exception)
         {
             LogLog.Error(typeof(VerboseLogger), message, exception);
@@ -15,5 +16,19 @@ public void Debug(string message)
         {
             LogLog.Debug(typeof(VerboseLogger), message);
         }
+        public void SetException(Exception exception)
+        {
+            threadException = exception;
+        }
+
+        public void CheckException()
+        {
+            Exception e = threadException;
+            if (threadException != null)
+            {
+                threadException = null;
+                throw e;
+            }
+        }
     }
 }

Source/EasyGelf.NLog/GelfTargetBase.cs

@@ -106,7 +106,9 @@ protected override void Write(LogEventInfo loggingEvent)
             catch (Exception exception)
             {
                 logger.Error("Failed to send message", exception);
+                throw;
             }
+            logger.CheckException();
         }
 
         protected override void InitializeTarget()

Source/EasyGelf.NLog/VerboseLogger.cs

@@ -6,6 +6,7 @@ namespace EasyGelf.NLog
 {
     public sealed class VerboseLogger : IEasyGelfLogger
     {
+        private static Exception threadException = null;
         public void Error(string message, Exception exception)
         {
             InternalLogger.Error(string.Format("{0} ---> {1}", message, exception));
@@ -15,5 +16,18 @@ public void Debug(string message)
         {
             InternalLogger.Debug(message);
         }
+        public void SetException(Exception exception)
+        {
+            threadException = exception;
+        }
+        public void CheckException()
+        {
+            Exception e = threadException;
+            if (threadException != null)
+            {
+                threadException = null;
+                throw e;
+            }
+        }
     }
 }