Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21004)
=item *
+If I<data> for a B<OSSL_PARAM_OCTET_STRING> or a
+B<OSSL_PARAM_UTF8_STRING> is NULL, the I<responder> should
+set I<return_size> to the size of the item to be returned
+and return success. Later the responder will be called again
+with I<data> pointing at the place for the value to be put.
+
+=item *
+
If a I<responder> finds that some data sizes are too small for the
requested data, it must set I<return_size> for each such
B<OSSL_PARAM> item to the minimum required size, and eventually return