Logging improvements suggestion for tsserver #14755

// Severity Levels
export enum LogLevel {
        FATAL = 60,
        ERROR = 50,
        WARN  = 40,
        INFO  = 30,
        DEBUG = 20,
        TRACE = 10,
        NONE  = 0
}


// Logger Interface
interface Logger {
  /**
  * Logger severity level 
  */
  level:LogLevel;

  /**
  * Logger category name
  */
  name:string; 

  // log level methods 
  fatal(message:string,extra?:any):[number,number];
  info(message:string,extra?:any):[number,number];
  /**
   * @param message Message to log 
   * @param extra Additional data associated to log 
   */
  trace(message:string,extra?:any):[number,number];
  
}

// Factory class 
class Logger {
    /**
     * Initializeing logger settings 
     * @param level Default log level 
     * @param useConsole Should use console 
     * @param useFile Should log to file 
     */
    init(level:LogLevel,useConsole:boolean,useFile:string):void{ /*...*/ }
    /**
     * Instantation of Logger
     * @param name Logger name / category
     */
    get(name:string):Logger{ return new Logger(); }
}

// Usage 

// Initialization of logger 
// https://github.com/casser/TypeScript/blob/bunyan-logger/src/server/server.ts#L406
Logger.init(LogLevel.TRACE,/*useConsole*/true,/*useFile*/"server.log"); // can be more options 


// Instantiation and usage of logger 
class MyLoggingTargetClass {
    logger:Logger;
    constructor(){
        //https://github.com/casser/TypeScript/blob/bunyan-logger/src/server/editorServices.ts#L279
        this.logger = Logger.get(this.constructor.name) // or Logger.get("Log Name")
    }

    someMethod(){
        // Logging simple message with extra data 
        // example: https://github.com/casser/TypeScript/blob/bunyan-logger/src/server/session.ts#L542
        this.logger.info("Message",{
            extra:"Data"
        })
        // Loggin message with conditional data fields 
        // This will log message when logger level > info but will add extra
        //   data {only_when:"Value"} only when logger level > debug, this will allow 
        //   add detailed information when we using high level of verbosity. 
        //   condition format is {key$level:value}  
        // example: https://github.com/casser/TypeScript/blob/bunyan-logger/src/server/session.ts#L196
        this.logger.info("Info message",{
            only_when$debug:"Value"
        })
        // Tracking performance  
        // Log methods returning hrtime array [sec,milisec] as and id of log 
        //   when this will be passed to next log that will count also duration 
        // example: https://github.com/casser/TypeScript/blob/bunyan-logger/src/server/session.ts#L1849
        let startTime  = this.logger.info("Action Started")
        someDelayedAction(()=>{
            // out
            // Action Sarted
            // Action End (actionDuration=22.256)
            this.logger.info("Action End",{
                actionDuration$time:startTime
            })
        })
    }
}