Rachel Chinouriri's success has been a slow burn. She prefers it that way

Mark SavageMusic CorrespondentLauren HarrisWhen Rachel Chinouriri played London's O2 Arena last month, she cried.The new wave indie songwriter was there as the support act for Sabrina Carpenter, just a week after her first Brit Awards, where she was nominated for artist of the year.Seven years after her debut single, those milestones felt like a validation. No wonder she shed a tear."A lot of it was stress…