static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
    bool status;
    pb_istream_t substream;
    const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
    
    if (!pb_make_string_substream(stream, &substream))
        return false;
    
    if (field->ptr == NULL)
        PB_RETURN_ERROR(stream, "invalid field descriptor");
    
    /* New array entries need to be initialized, while required and optional
     * submessages have already been initialized in the top-level pb_decode. */
    if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
        status = pb_decode(&substream, submsg_fields, dest);
    else
        status = pb_decode_noinit(&substream, submsg_fields, dest);
    
    pb_close_string_substream(stream, &substream);
    return status;
}