'Creates an empty memory BIO.'

def _create_mem_bio_gc(self):

    bio_method = self._lib.BIO_s_mem()
    self.openssl_assert((bio_method != self._ffi.NULL))
    bio = self._lib.BIO_new(bio_method)
    self.openssl_assert((bio != self._ffi.NULL))
    bio = self._ffi.gc(bio, self._lib.BIO_free)
    return bio
