question: format the elapsed time to a human understandable string . note : if timer is never started , `` err '' will be returned . concode_field_sep boolean started concode_elem_sep long last concode_elem_sep long cumulate concode_field_sep boolean readable concode_elem_sep long read concode_elem_sep void stop concode_elem_sep String nanoTimeToString concode_elem_sep void start concode_elem_sep void reset concode_elem_sep void main concode_elem_sep boolean isStarted
target: String function ( ) { if ( ! readable ( ) ) { return "srini_string" ; } return NanoTimer . nanoTimeToString ( this . cumulate ) ; }