public static io.netty.handler.codec.http.HttpHeaders toNettyHttp1ClientHeaders(HttpHeaders inputHeaders) {
        if (inputHeaders.isEmpty()) {
            return EmptyHttpHeaders.INSTANCE;
        }

        final io.netty.handler.codec.http.HttpHeaders outputHeaders = new DefaultHttpHeaders(false);
        toNettyHttp1Client(inputHeaders, outputHeaders, Http1HeaderNaming.ofDefault(), false);
        return outputHeaders;
    }
Translates and adds HTTP/2 request headers to HTTP/1.1 headers.

@param inputHeaders the HTTP/2 request headers to convert.
core/src/main/java/com/linecorp/armeria/internal/common/ArmeriaHttpUtil.java