Read this article carefully.  The article itself does not directly state that Iran used the Iraq PM to pass warning to the U.S. about the large attack against Ain al-Asad.  “Iran Alerted US Before Soleimani Revenge Strike, Zarif Affirms,” Iran International, 3-23-24.  It makes no sense (and it is out of character) for Iran or the IRGC to warn America.