cloneWithDifferentAllocator

    pub fn cloneWithDifferentAllocator(other: Managed, allocator: Allocator) !Managed {
        return .{
            .allocator = allocator,
            .metadata = other.metadata,
            .limbs = block: {
                const limbs = try allocator.alloc(Limb, other.len());
                @memcpy(limbs, other.limbs[0..other.len()]);
                break :block limbs;
            },
        };
    }