Log failiures to post to Splunk to the Debug window, as well as cathing the exception that exited the post loop.

Author: Coleman, Christopher

src/ColeSoft.Extensions.Logging.Splunk/Hec/SplunkProviderBase.cs

@@ -160,6 +160,10 @@ private async Task SendToSplunkInternalAsync(IReadOnlyList<string> messages)
             {
                 await SendToSplunkAsync(messages);
             }
+            catch (Exception e)
+            {
+                Debug.Write(e, "Failed to send log messages to Splunk");
+            }
             finally
             {
                 httpClientSemaphore.Release();