在HttpServletRequest的headerNames枚举上使用Collectors.toMap创建HttpHeaders时发生编译错误

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.core.HttpHeaders;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Example {
    public HttpHeaders createHttpHeaders(HttpServletRequest request) {
        Enumeration<String> headerNames = request.getHeaderNames();
        Map<String, String> headers = Collections.list(headerNames)
                .stream()
                .collect(Collectors.toMap(
                        headerName -> headerName,
                        headerName -> request.getHeader(headerName)
                ));
        return new HttpHeadersImpl(headers);
    }
}

class HttpHeadersImpl implements HttpHeaders {
    private final Map<String, String> headers;

    public HttpHeadersImpl(Map<String, String> headers) {
        this.headers = headers;
    }

    // 实现HttpHeaders接口的其他方法
}