"The Messenger of Allah ﷺ said: 'Bilal calls the Adhan during the night, so eat and drink until Ibn Umm Maktum calls the Adhan." She said: "And there was no more between than the time it takes for one to come down and the other to go up." (Using translation from Nasāʾī 639)
قَالَ رَسُولُ اللهِ ﷺ «إِذَا أَذَّنَ بِلَالٌ فَكُلُوا وَاشْرَبُوا حَتَّى يُؤَذِّنَ ابْنُ أُمَّ مَكْتُومٍ» قَالَتْ وَلَمْ يَكُنْ بَيْنَهُمَا إِلَّا أَنْ يَنْزِلَ هَذَا وَيَصْعَدَ هَذَا