Remove vec! allocations

[jabuwu]

For better integration with Rust, the C code was modified to allocate some vectors (search for the vec! macro in lib.rs). There's probably a better way to do this, avoiding the allocations.

[jabuwu]

Fixed in 033fb1f

Allocations were removed using some slice trickery. Given that we know the max size, we can allocate a slice array on the stack instead of using a vector.

rusty_enet/src/c/protocol.rs

Lines 2213 to 2224 in 033fb1f

	let mut in_buffers: [&[u8]; ENET_BUFFER_MAXIMUM as usize] =
	std::array::from_fn(|_| {
	from_raw_parts_or_empty::<u8>(std::ptr::null(), 0)
	});
	#[allow(clippy::needless_range_loop)]
	for i in 0..((*host).buffer_count).wrapping_sub(1) {
	let buffer = ((*host).buffers).as_mut_ptr().add(1 + i);
	in_buffers[i] = super::from_raw_parts_or_empty(
	(*buffer).data,
	(*buffer).data_length,
	);
	}

The send and peer allocations still exist. The peer one exists in ENet, so that's fine. It was changed to at least reserve the peer count ahead of time before pushing the peers.

The send allocation is worth keeping since most socket implementations will likely want to do this, anyway. It was changed to reserve the buffer count in 6fe949c. It could avoid this allocation if compression is disabled, but one allocation during send seems pretty harmless.