Function with 

pub fn with<F, O>(f: F) -> O
where
    F: FnOnce(&Default<'_>) -> O,

Call the given closure with the default allocator.

This is useful if you want to write application which are agnostic to whether the alloc feature is or isn’t enabled.

• If the alloc feature is enabled, this is the System allocator.
• If the alloc feature is disabled, this is the Stack allocator with DEFAULT_STACK_BUFFER bytes allocated on the stack.

Examples

use musli::{Allocator, Buf};

musli_allocator::with(|alloc| {
    let mut a = alloc.alloc().expect("allocation a failed");
    let mut b = alloc.alloc().expect("allocation b failed");

    b.write(b"He11o");
    a.write(b.as_slice());

    assert_eq!(a.as_slice(), b"He11o");
    assert_eq!(a.len(), 5);

    a.write(b" W0rld");

    assert_eq!(a.as_slice(), b"He11o W0rld");
    assert_eq!(a.len(), 11);

    let mut c = alloc.alloc().expect("allocation c failed");
    c.write(b"!");
    a.write(c.as_slice());

    assert_eq!(a.as_slice(), b"He11o W0rld!");
    assert_eq!(a.len(), 12);
});