#[no_mangle]
pub unsafe extern "C" fn new(
array: *const Entity,
length: c_int,
time_step: c_double
) -> *mut c_void
The exported FFI version of [GravTree]'s new() method. Returns a void pointer to the location
in memory where the [GravTree] is located. Use this void pointer to tell Rust where to look for
the tree in the other FFI functions.