Could you guide me how to investigate the traffic with Wireshark?

I know how to use Wireshark, but I can't figure out how to investigate multiple HTTP request handled "at the same" time. 

The data was transmitted through SSL, so I can't distinguish those data came from different requests.

Hi,

HTTP/2 support in Web HTTP/HTML and DevWeb protocols means that it works as described. Virtual user utilize one connection per server and multiple HTTP request handled "at the same" time. HTTP/2 support enabled by default in Run-Time settings ("Preferences > HTTP > Enable HTTP/2 features"  for Web HTTP/HTML protocol and "Settings > SSL > Enable HTTP/2" for DevWeb). When virtual user performs SSL handshake with web server, it supplies the appropriate "flag" to the server and once it accepted, communication will be done using HTTP/2.

You can investigate the traffic with Wireshark. 

Best regards,

Leonid.

HTTP/2 allows you to send off multiple requests on the same connection at the same time (multiplexing). Does LR support this function? If YES, how to use it?

Right....Currently most the enterprise applications and products are responsive in nature to provide support on multiple clients....Currently TruClient Mob Web protocol has support for http1.1 on LR2023....we must have support for http 2.0 unanimously.