static RequestHeaders of(HttpMethod method, String path,
                             CharSequence name1, Object value1,
                             CharSequence name2, Object value2) {
        return builder(method, path).addObject(name1, value1)
                                    .addObject(name2, value2)
                                    .build();
    }
Returns a new {@link RequestHeaders} with the specified {@link HttpMethod}, {@code path} and
additional headers. The values are converted into {@link String}s as explained in
<a href="HttpHeaders.html#object-values">Specifying a non-String header value</a>.
core/src/main/java/com/linecorp/armeria/common/RequestHeaders.java