using System; namespace ContosoUniversity.Logging { public interface ILogger { void Information(string message); void Information(string fmt, params object[] vars); void Information(Exception exception, string fmt, params object[] vars); void Warning(string message); void Warning(string fmt, params object[] vars); void Warning(Exception exception, string fmt, params object[] vars); void Error(string message); void Error(string fmt, params object[] vars); void Error(Exception exception, string fmt, params object[] vars); void TraceApi(string componentName, string method, TimeSpan timespan); void TraceApi(string componentName, string method, TimeSpan timespan, string properties); void TraceApi(string componentName, string method, TimeSpan timespan, string fmt, params object[] vars); } }