Ruslan Alikhamov, Senior iOS Engineer at Qonto, presented a session titled "IT'S RAW! Enhancing iOS Developer Experience with Swift Compiler Output & Xcode" where he focused on reducing the compilation duration of an iOS codebase by more than 50% and improving developer experience. Ruslan's team solved this problem by addressing issues with Xcode handling large Swift Source files, which led to a significant improvement in unit test compilation time from 9 minutes 37 seconds to under 4 minutes. The solution involved leveraging Xcode facilities for measuring build performance, using Swift compiler output for better developer experience, and resolving common swift code compilation slowness issues through an internal company-wide hackathon that improved overall developer experience and innovation.