# Microsoft.Extensions.Logging

``` diff
 namespace Microsoft.Extensions.Logging {
     public static class FilterLoggingBuilderExtensions {
-        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, Func<string, LogLevel, bool> categoryLevelFilter);
+        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, Func<string?, LogLevel, bool> categoryLevelFilter);
-        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, Func<string, string, LogLevel, bool> filter);
+        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, Func<string?, string?, LogLevel, bool> filter);
-        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, string category, LogLevel level);
+        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, string? category, LogLevel level);
-        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, string category, Func<LogLevel, bool> levelFilter);
+        public static ILoggingBuilder AddFilter(this ILoggingBuilder builder, string? category, Func<LogLevel, bool> levelFilter);
-        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, Func<string, LogLevel, bool> categoryLevelFilter);
+        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, Func<string?, LogLevel, bool> categoryLevelFilter);
-        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, Func<string, string, LogLevel, bool> filter);
+        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, Func<string?, string?, LogLevel, bool> filter);
-        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, string category, LogLevel level);
+        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, string? category, LogLevel level);
-        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, string category, Func<LogLevel, bool> levelFilter);
+        public static LoggerFilterOptions AddFilter(this LoggerFilterOptions builder, string? category, Func<LogLevel, bool> levelFilter);
-        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, Func<string, LogLevel, bool> categoryLevelFilter) where T : ILoggerProvider;
+        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, Func<string?, LogLevel, bool> categoryLevelFilter) where T : ILoggerProvider;
-        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, string category, LogLevel level) where T : ILoggerProvider;
+        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, string? category, LogLevel level) where T : ILoggerProvider;
-        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, string category, Func<LogLevel, bool> levelFilter) where T : ILoggerProvider;
+        public static ILoggingBuilder AddFilter<T>(this ILoggingBuilder builder, string? category, Func<LogLevel, bool> levelFilter) where T : ILoggerProvider;
-        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, Func<string, LogLevel, bool> categoryLevelFilter) where T : ILoggerProvider;
+        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, Func<string?, LogLevel, bool> categoryLevelFilter) where T : ILoggerProvider;
-        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, string category, LogLevel level) where T : ILoggerProvider;
+        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, string? category, LogLevel level) where T : ILoggerProvider;
-        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, string category, Func<LogLevel, bool> levelFilter) where T : ILoggerProvider;
+        public static LoggerFilterOptions AddFilter<T>(this LoggerFilterOptions builder, string? category, Func<LogLevel, bool> levelFilter) where T : ILoggerProvider;
     }
     public class LoggerFactory : IDisposable, ILoggerFactory {
-        public LoggerFactory(IEnumerable<ILoggerProvider> providers, IOptionsMonitor<LoggerFilterOptions> filterOption, IOptions<LoggerFactoryOptions> options = null);
+        public LoggerFactory(IEnumerable<ILoggerProvider> providers, IOptionsMonitor<LoggerFilterOptions> filterOption, IOptions<LoggerFactoryOptions>? options = null);
     }
 }
```

