# no channel usage at all (baseline)
 Duration: 75.269999999989523
 Lines: 838663 (position: 55181312, 23.77%)
 Rate: 11142.061910457243

 # channel.push obj.to_json
 Duration: 75.680000000022119
 Lines: 612806 (position: 41025536, 17.67%)
 Rate: 8097.3308668052441

 # channel.push 1 # (in case 'obj.to_json' was consuming time)
 Duration: 75.459999999991851
 Lines: 700935 (position: 46792704, 20.15%)
 Rate: 9288.8285184213582

 # channel.push obj.to_json if subscribers > 0
 Duration: 75.279999999998836
 Lines: 850888 (position: 55902208, 24.08%)
 Rate: 11302.975557917283