Update ILogger.md

Author: usa-m

docs/usage/ILogger.md

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+# ILogger
+
+DDS.Net.Connector.Interfaces.**ILogger** is the main logging interface used by the library. The interface is simple and only includes three methods:
+
+  * void Info(string message) - Used to write information-level message to log.
+  * void Warning(string message) - Used to write warning-level message to log.
+  * void Error(string message) - Used to write error-level message to log.
+
+ 
+
+For simplicity, the library includes following default implementations for the interface:
+
+  * DDS.Net.Connector.Interfaces.DefaultLogger.**BlankLogger** - discards all the log messages.
+  * DDS.Net.Connector.Interfaces.DefaultLogger.**ConsoleLogger** - prints log messages on the standard console.
+  * DDS.Net.Connector.Interfaces.DefaultLogger.**FileLogger** - prints log messages into a given file.
+  * DDS.Net.Connector.Interfaces.DefaultLogger.**SplitLogger** - splits log messages between two or more *ILogger* implementations
+
+