Psych::Emitter#start_document

static VALUE start_document(VALUE self, VALUE version, VALUE tags, VALUE imp)
{
    struct start_document_data data = {
        .self = self,
        .version = version,
        .tags = tags,
        .imp = imp,

        .head = NULL,
    };

    return rb_ensure(start_document_try, (VALUE)&data, start_document_ensure, (VALUE)&data);
}