Function nt_protect_virtual_memory 

pub fn nt_protect_virtual_memory(
    handle: HANDLE,
    base_address: *mut PVOID,
    size: *mut usize,
    new_protection: u32,
    old_protection: *mut u32,
) -> i32

Available on x86-64 only.

Dynamically calls NtProtectVirtualMemory.

It will return the NTSTATUS value returned by the call.