AppSync Documentation not disclosing restricted headers, which include auth and encoding headers among others.

Hello Team,

- Xray Tracing Servicemap not working as expected when we use **$util.http.copyHeaders($ctx.request.headers)**

- After further investigation AppSync Service team confirmed that **X-Amzn-Trace-Id** header modification causing issue in Xray trace service mapping.

- As per the documentation [http-helpers-in-utils-http-js](https://docs.aws.amazon.com/appsync/latest/devguide/http-helpers-in-utils-http-js.html) it seems to indicate that it will not forward "the restricted set of HTTP headers" but The trace header is not restricted in **copyHeaders** utility.

- Please update the required documentation to disclose these restricted headers, which include auth and encoding headers among others.

- We could use below solutions to move past this Xray trace service mapping issue.

1. Remove the header from the list.
2. Add required headers as per your use instead of forwarding all headers.

Start with the linked AppSync HTTP helpers documentation, especially the copyHeaders utility and its description of restricted headers. Update the documentation to disclose that X-Amzn-Trace-Id and the relevant auth and encoding headers are restricted; done means users can identify restricted headers and understand the suggested alternatives.

Written by the indexing model from the issue text.