For Issue: #5781

What is the purpose of the change

Once we are going to extend the serialization, write direct to Hessian InputStream/OutputStream is high efficient on the memroy.

Brief changelog

Currently, the InputStream/OutputStream is not exported. The change is going to export the InputStream/OutputStream from Hessian2ObjectInput and Hessian2ObjectOutput.

private final Hessian2ObjectOutput delegate;

protected ProtobufObjectOutput(OutputStream os) {
  this.delegate = new Hessian2ObjectOutput(os);
}

void writeBytesForPBObject(Object obj, Class clazz) throws IOException {
  try (OutputStream os = delegate.getOutputStream()) {
    if (obj instanceof MessageLite) {
      try {
        ((MessageLite) obj).writeTo(os);
      } catch (IOException e) {
        throw new RuntimeException("Google PB序列化失败，序列化对象的类型为" + obj.getClass().getName(), e);
      }
    }
  }
}

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