I'm looking for an experienced mobile app developer to create a feature-rich messenger application available on both iOS and Android platforms. Core functionalities include: - Text messaging - Voice calls - Video calls Additional features: - Media sharing (images, videos) - Group chat - End-to-end encryption for privacy and security Ideal skills and experience: - Proficiency in mobile app development for both iOS and Android - Experience with real-time communication features - Strong background in implementing end-to-end encryption and data security - Ability to create intuitive and user-friendly interfaces Please provide examples of similar work done and an estimated timeline for completion.