@Override
    public Builder toBuilder() {
        return builder()
                .extensions(getExtensions())
                .description(description)
                .headers(headers)
                .content(content)
                .links(links);
    }
Gets a header by case-insensitive header name.

@param header Header to retrieve.
@return Returns the optionally found header.
smithy-openapi/src/main/java/software/amazon/smithy/openapi/model/ResponseObject.java