Energy Transfer (ET 6.74%) is a large midstream master limited partnership (MLP). The big attraction for most investors here will be the lofty 7.8% yield backed by a growing distribution. In fact, the quarterly distribution was just increased again, extending the MLP's quarterly increase streak that started in the fourth quarter of 2021.But is Energy Transfer stock worth buying while it's trading below $20?What does Energy Transfer do?As noted, Energy Transfer is an MLP that operates in the midstream sector ...