Method update

src/vol.rs:104–113

Use specified closure and volatile instruction(s) to update contained value:

(&mut self, f: F)

	// Use specified closure and volatile instruction(s) to update contained value:
	pub fn update<F>(&mut self, f: F)
	where
		A: CanRead + CanWrite,
		R: DerefMut,
		F: FnOnce(&mut T),
	{
		let mut value = self.read();
		f(&mut value);
		self.write(value);
	}
}