How to specify correct encoding in PHPStorm?

Question

phpstorm

Hello!
Tell me how to specify UTF-8 encoding in PHPStorm -> Tools -> Test Resful Web Service (PS is a REST Client plugin)?
Problem:
I send, for example, a POST request, I enter Russian text in the request parameters, and the script in $_POST receives no longer readable text (and this is not even a scribble, but just "diamonds with a question mark").
Only Latin comes in a readable form. Through the browser the text is readable.
Tried headers Content-Type application/x-www-form-urlencoded; charset=utf-8, the title comes in, but the text is still unreadable.
Are there solutions?