<s> from __future__ import absolute_import <EOL> from concurrent . futures import Future <EOL> from . span import Span <EOL> class Tracer ( object ) : <EOL> """<STR_LIT>""" <EOL> def __init__ ( self ) : <EOL> self . _noop_span = Span ( self ) <EOL> def start_span ( self , <EOL> operation_name = None , <EOL> parent = None , <EOL> tags = None , <EOL> start_time = None ) : <EOL> """<STR_LIT>""" <EOL> return self . _noop_span <EOL> def inject ( self , span , format , carrier ) : <EOL> """<STR_LIT>""" <EOL> pass <EOL> def join ( self , operation_name , format , carrier ) : <EOL> """<STR_LIT>""" <EOL> return self . _noop_span <EOL> def flush ( self ) : <EOL> """<STR_LIT>""" <EOL> fut = Future ( ) <EOL> fut . set_result ( True ) <EOL> return fut </s>
