Question about the fix v1.1.4 Throttling Exeption: Rate exceeded

[Encorpluptit]

Hi,

Infra guy here, not familliar with php, symfony, composer ,etc...
Recently, I encountered a "Throttling Exeption: Rate exceeded" in our php legacy code that use this library with version v1.1.1.

My question is about the fix introduced in the v1.1.4.
Does the sleep will pause the execution of the HTTP request ? Or is this library handled in another thread or in an asynchronous way and will log when it can without pausing the execution of the request ?

Our legacy application use Symfony 2.8 with php 7.2. It's not possible to update these two.

Thanks in advance.