It is narrated from Humaid bin Abdur Rahman bin Awf that Umar and Uthman (may Allah be pleased with them) used to perform the Maghrib prayer when they saw the darkness of the night, and then after the prayer they would break their fast. This was during Ramadan.
Hadith Referenceمسند الإمام الشافعي / كتاب الصيام / 613
Hadith Takhrijاسناده ضعيف لإرساله اخرجه البيهقي : 4 / 238 ۔ وفي المعرفة السنن والآثار له (2506) ـ وعبدالرزاق (7588)۔
It is narrated from Sahl bin Sa’d Al-Sa’idi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: People will remain upon goodness as long as they hasten in breaking the fast.
Hadith Referenceمسند الإمام الشافعي / كتاب الصيام / 614
Hadith Takhrijاخرجه البخاري، الصوم، باب تعجيل الأفطار (1957) ومسلم، الصيام، باب فضل السحور وتأكيد استحبابه واستحباب تأخيره وتعجيل الفطر (1098)۔