Charge power bank and discharge to charge phone at same time

Quick googling to demystify this, i used a few other not known brands power bank before and they either never work at all (lol) or only discharge once or just don't last.

Reckon you guys probably get here through the title keyword =)
The term i'm looking for is probably this ‘Pass through Charging’ , credit to geckoandfly review of Xiaomi power bank specifically.

Excerpt from the review:
"Unlike other power bank, XiaoMi Mobile powerbank comes with ‘Pass through Charging’ capability. This enables you to charge the powerbank and your smartphone all at the same time. Most power banks are not able to ‘dual charge’ both the powerbank and smartphone at the same time."

Another argument from Mr Devan here:

I'm using the 16000 version and yes it's the best in its class in my own experience so far & at the price of RM6x for this and if i remember correctly <RM50 for the 10kA capacity version this is probably your best friend's best friend.

Guess the conclusion is;don't have to worry about microUSB/USB gangbangs party on the powerbank now, looks legit and don't need to expect any fireworks or KO party... at least with Xiaomi's power bank.

Update: No problem! so far i don't see any degradation to both my Xiaomi power bank & phone battery. It's 3 years old Samsung Note 2 and hopefully can take my abuse on it's battery usage for another year or so, all still using original battery & parts, no history of change except for it's screen protection & cover.