@Override
    public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
            throws HttpException, IOException {
        Args.notNull(request, "HTTP request");
        Args.notNull(context, "HTTP context");

        final HttpClientContext clientContext = HttpClientContext.cast(context);
        final String exchangeId = clientContext.getExchangeId();

        final AuthCache authCache = clientContext.getAuthCache();
        if (authCache == null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("{} Auth cache not set in the context", exchangeId);
            }
            return;
        }

        final CredentialsProvider credsProvider = clientContext.getCredentialsProvider();
        if (credsProvider == null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("{} Credentials provider not set in the context", exchangeId);
            }
            return;
        }

        final RouteInfo route = clientContext.getHttpRoute();
        if (route == null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("{} Route info not set in the context", exchangeId);
            }
            return;
        }

        final HttpHost target = new HttpHost(request.getScheme(), request.getAuthority());
        final AuthExchange targetAuthExchange = clientContext.getAuthExchange(target);
        if (targetAuthExchange.getState() == AuthExchange.State.UNCHALLENGED) {
            final String pathPrefix = RequestSupport.extractPathPrefix(request);
            final AuthScheme authScheme = authCache.get(target, pathPrefix);
            if (authScheme != null) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("{} Re-using cached '{}' auth scheme for {}", exchangeId, authScheme.getName(), target);
                }
                targetAuthExchange.select(authScheme);
            }
        }

        final HttpHost proxy = route.getProxyHost();
        if (proxy != null) {
            final AuthExchange proxyAuthExchange = clientContext.getAuthExchange(proxy);
            if (proxyAuthExchange.getState() == AuthExchange.State.UNCHALLENGED) {
                final AuthScheme authScheme = authCache.get(proxy, null);
                if (authScheme != null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("{} Re-using cached '{}' auth scheme for {}", exchangeId, authScheme.getName(), proxy);
                    }
                    proxyAuthExchange.select(authScheme);
                }
            }
        }
    }
Request interceptor that can preemptively authenticate against known hosts,
if there is a cached {@link AuthScheme} instance in the local
{@link AuthCache} associated with the given target or proxy host.

@since 4.1

@deprecated Do not use.
httpclient5/src/main/java/org/apache/hc/client5/http/protocol/RequestAuthCache.java