How to return an array of any dimenion from pl/rust function.

[thiru-baffle]

We are converting the UDFs from PL/PGSQL to PL/Rust.
The following pl/pgsql function accepts an array of bigint and returns an array of bytea.

1. create function array_encrypt(xs anyarray) returns bytea[].

With this function, it can accept any dimension of an array and can return any dimension array by returning an array[[data::bytea][data2::bytea]].

To do this same thing in pl/rust, I have tried a few things as below:

1. CREATE FUNCTION echo_array(a INT[]) RETURNS int[] STRICT LANGUAGE pl/rust AS -> it always expects the return type of Vec<Option>
2. I have noticed that when the function argument is of array type, then pl/rust accepts it as Array<'_, i32>. So I tried

CREATE FUNCTION echo_fn_2(a INT[]) RETURNS Array<', i32> -> But failed to recognize the Array<',i32> type in pl/rust.

Could you help me, is there any options to achieve the above requirement in pl/rust?