International Forum on Transfusion Practices in Haematopoietic Stem‐Cell Transplantation: Summary. Issue 5 (18th April 2021) - Solves, Pilar; Lozano, Miquel; Zhiburt, Eugene; Anguita Velasco, Javier; Maria Pérez‐Corral, Ana; Monsalvo‐Saornil, Silvia; Yamazaki, Sho; Okazaki, Hitoshi; Selleng, Kathleen; Aurich, Konstanze; Krüger, William; Buser, Andreas; et al.