Worked on improving event streaming reliability in the symfony/symfony repository by addressing a bug in the EventSourceHttpClient component. Focused on preventing duplicate emission of the first data chunk after a client reconnection, which previously led to data duplication and user-visible errors in real-time updates. Introduced a tracking mechanism to identify if the first chunk had already been processed and refined the yielding logic to avoid re-processing. Utilized PHP for backend development and applied unit testing to ensure robustness. This targeted fix enhanced the stability of live event streams, resulting in a smoother experience for end users within the Symfony ecosystem.