private static boolean isWebSocketUpgrade(io.netty.handler.codec.http.HttpHeaders inHeaders) {
        final boolean isUpgrade = findDelimitedIgnoreCase(HttpHeaderNames.CONNECTION,
                                                          HttpHeaderValues.UPGRADE, inHeaders);
        final boolean isWebsocket = findDelimitedIgnoreCase(HttpHeaderNames.UPGRADE,
                                                            HttpHeaderValues.WEBSOCKET, inHeaders);
        return isUpgrade && isWebsocket;
    }
Removes HTTP/1 specified headers from a mutable headers map.
Functionally this method is expected to behave the same as
{@link #toArmeria(io.netty.handler.codec.http.HttpHeaders, HttpHeadersBuilder)}.
This method should be preferred going forward as we continue implementing zero-copy
for HTTP1 en/decoders.
core/src/main/java/com/linecorp/armeria/internal/common/ArmeriaHttpUtil.java