pub fn mut_ctx<'a, T: Any>(&'a mut self) -> Option<&'a mut T> {
        self.user_ctx
            .get_mut(&TypeId::of::<T>())
            .map(|a| a.downcast_mut().unwrap())
    }
/// Get context of a given type. Exactly one value per type may be stored.
Get context of a given type. Exactly one value per type may be stored.
Get context of a given type . Exactly one value per type may be stored .
pub fn mut_ctx<'a, T: Any>(&'a mut self) -> Option<&'a mut T> {
        self.user_ctx
            .get_mut(&TypeId::of::<T>())
            .map(|a| a.downcast_mut().unwrap())
    }
pub fn mut_ctx < ' a , T : Any > ( & ' a mut self ) -> Option < & ' a mut T > { self . user_ctx . get_mut ( & TypeId :: of :: < T > ( ) ) . map ( | a | a . downcast_mut ( ) . unwrap ( ) ) }
Get context of a given type.
Get context of a given type .
&'a mut self
&'a mut self