The Prophet ﷺ said, "Bilal pronounces the Adhan when it is still night (before dawn), so eat and drink till the next Adhan is pronounced (or till you hear Ibn Um Maktum's Adhan)." Ibn Um Maktum was a blind man who would not pronounce the Adhan till he was told that it was dawn.
قَالَ النَّبِيُّ ﷺ إِنَّ بِلاَلاً يُؤَذِّنُ بِلَيْلٍ فَكُلُوا وَاشْرَبُوا حَتَّى يُؤَذِّنَ أَوْ قَالَ حَتَّى تَسْمَعُوا أَذَانَ ابْنِ أُمِّ مَكْتُومٍ وَكَانَ ابْنُ أُمِّ مَكْتُومٍ رَجُلاً أَعْمَى لاَ يُؤَذِّنُ حَتَّى يَقُولَ لَهُ النَّاسُ أَصْبَحْتَ