Function manage_os_memory 

pub unsafe fn manage_os_memory(
    start: *mut u8,
    size: usize,
    is_committed: bool,
    is_pinned: bool,
    is_zero: bool,
    numa_node: i32,
    exclusive: bool,
) -> Result<ArenaId, ArenaError>

Manage an existing memory region as an arena.

Safety

start must point to at least size valid bytes that outlive the arena.