pub fn extend_from_slice(&mut self, src: &[T]) {
        let new_len = self.len + src.len();
        if new_len > self.cap {
            self.grow(new_len);
        }
        let old_len = self.len;
        let uninit_slice = &mut self.inner_mut().body[old_len..];
        unsafe {
            ptr::copy(
                src.as_ptr() as *mut MaybeUninit<T>,
                uninit_slice.as_mut_ptr(),
                src.len(),
            )
        }
        self.len = new_len;
    }
/// Copies the contents onto the end of the vector.
Copies the contents onto the end of the vector.
Copies the contents onto the end of the vector .
pub fn extend_from_slice(&mut self, src: &[T]) {
        let new_len = self.len + src.len();
        if new_len > self.cap {
            self.grow(new_len);
        }
        let old_len = self.len;
        let uninit_slice = &mut self.inner_mut().body[old_len..];
        unsafe {
            ptr::copy(
                src.as_ptr() as *mut MaybeUninit<T>,
                uninit_slice.as_mut_ptr(),
                src.len(),
            )
        }
        self.len = new_len;
    }
pub fn extend_from_slice ( & mut self , src : & [ T ] ) { let new_len = self . len + src . len ( ) ; if new_len > self . cap { self . grow ( new_len ) ; } let old_len = self . len ; let uninit_slice = & mut self . inner_mut ( ) . body [ old_len .. ] ; unsafe { ptr :: copy ( src . as_ptr ( ) as * mut MaybeUninit < T > , uninit_slice . as_mut_ptr ( ) , src . len ( ) , ) } self . len = new_len ; }
Copies the contents onto the end of the vector.
Copies the contents onto the end of the vector .
&mut self
src
&[T]