code: void writeCompoundAttribute(Attribute.Compound c) {
          databuf.appendChar(pool.put(typeSig(c.type)));
          databuf.appendChar(c.values.length());
          for (Pair<Symbol.MethodSymbol,Attribute> p : c.values) {
              databuf.appendChar(pool.put(p.fst.name));
              p.snd.accept(awriter);
          }
      }
docs: Write a compound attribute excluding the '@' marker.