256     /// additional` elements. If it doesn't already have enough capacity, will
276     pub fn reserve(&mut self, len: usize, additional: usize) {  in reserve()
285             additional: usize,  in reserve()
287             handle_reserve(slf.grow_amortized(len, additional));  in reserve()
290         if self.needs_to_grow(len, additional) {  in reserve()
291             do_reserve_and_handle(self, len, additional);  in reserve()
304     pub fn try_reserve(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {  in try_reserve()
305         if self.needs_to_grow(len, additional) {  in try_reserve()
306             self.grow_amortized(len, additional)  in try_reserve()
319     /// additional` elements. If it doesn't already, will reallocate the
336     pub fn reserve_exact(&mut self, len: usize, additional: usize) {  in reserve_exact()
337         handle_reserve(self.try_reserve_exact(len, additional));  in reserve_exact()
344         additional: usize,  in try_reserve_exact()
346         if self.needs_to_grow(len, additional) { self.grow_exact(len, additional) } else { Ok(()) }  in try_reserve_exact()
368     fn needs_to_grow(&self, len: usize, additional: usize) -> bool {  in needs_to_grow()
369         additional > self.capacity().wrapping_sub(len)  in needs_to_grow()
387     fn grow_amortized(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {  in grow_amortized()
389         debug_assert!(additional > 0);  in grow_amortized()
398         let required_cap = len.checked_add(additional).ok_or(CapacityOverflow)?;  in grow_amortized()
416     fn grow_exact(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {  in grow_exact()
423         let cap = len.checked_add(additional).ok_or(CapacityOverflow)?;  in grow_exact()