FL.init(new FLConfig.Builder(this)
        .logger(...)       // customise how to hook up with logcat
        .defaultTag("Default Tag")   // customise default tag
        .minLevel(FLConst.Level.V)   // customise minimum logging level
        .logToFile(true)   // enable logging to file
        .dir(directory)    // customise directory to hold log files
        .formatter(...)    // customise log format and file name
        .retentionPolicy(FLConst.RetentionPolicy.FILE_COUNT) // customise retention strategy
        .maxFileCount(FLConst.DEFAULT_MAX_FILE_COUNT)    // customise how many log files to keep if retention by file count
        .maxTotalSize(FLConst.DEFAULT_MAX_TOTAL_SIZE)    // customise how much space log files can occupy if retention by total size
        .build());
        
        
// overall toggle to enable/disable logging
FL.setEnabled(true);

// to log with default tag
FL.d("this is a debug message");

// to log with placeholder and interpolation
FL.d("this is a %s message", "debug");

// to log with specified tag
FL.d("Tag", "this is a %s message", "debug");

// to log exception
FL.e("Tag", throwable);
FL.e("Tag", throwable, "extra %s info", "debug");