Removed obsolete exceptions handlers

The sink had exceptions handlers when log events could not be written. Those handlers wrote an error message using Serilog's SelfLog() facility. This is now done by the Serilog Core when a sink's Emit() and EmitBatchAsync() methods throw an exception. This is why can remove our handlers, let exceptions propagate and Serilog Core do the work.

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/Platform/SqlBulkBatchWriter.cs

@@ -60,12 +60,6 @@ public async Task WriteBatch(IEnumerable<LogEvent> events)
                     }
                 }
             }
-            catch (Exception ex)
-            {
-                SelfLog.WriteLine("Unable to write batch of {0} log events to the database due to following error: {1}",
-                    events.Count(), ex);
-                throw;
-            }
             finally
             {
                 _dataTable.Clear();

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/Platform/SqlInsertStatementWriter.cs

@@ -43,34 +43,26 @@ public SqlInsertStatementWriter(
 
         public async Task WriteEvents(IEnumerable<LogEvent> events)
         {
-            try
+            using (var cn = _sqlConnectionFactory.Create())
             {
-                using (var cn = _sqlConnectionFactory.Create())
+                await cn.OpenAsync().ConfigureAwait(false);
+
+                foreach (var logEvent in events)
                 {
-                    await cn.OpenAsync().ConfigureAwait(false);
+                    var fields = _logEventDataGenerator.GetColumnsAndValues(logEvent).ToList();
+                    InitializeSqlCommand(cn, fields);
 
-                    foreach (var logEvent in events)
+                    var index = 0;
+                    _sqlCommand.ClearParameters();
+                    foreach (var field in fields)
                     {
-                        var fields = _logEventDataGenerator.GetColumnsAndValues(logEvent).ToList();
-                        InitializeSqlCommand(cn, fields);
-
-                        var index = 0;
-                        _sqlCommand.ClearParameters();
-                        foreach (var field in fields)
-                        {
-                            _sqlCommand.AddParameter(Invariant($"@P{index}"), field.Value);
-                            index++;
-                        }
-
-                        await _sqlCommand.ExecuteNonQueryAsync().ConfigureAwait(false);
+                        _sqlCommand.AddParameter(Invariant($"@P{index}"), field.Value);
+                        index++;
                     }
+
+                    await _sqlCommand.ExecuteNonQueryAsync().ConfigureAwait(false);
                 }
             }
-            catch (Exception ex)
-            {
-                SelfLog.WriteLine("Unable to write log event to the database due to following error: {0}", ex);
-                throw;
-            }
         }
 
         /// <summary>