public AbstractClientContextBuilder<T> preemptiveBasicAuth(final HttpHost host, final UsernamePasswordCredentials credentials) {
        Args.notNull(host, "HTTP host");
        final BasicScheme authScheme = new BasicScheme();
        authScheme.initPreemptive(credentials);
        preemptiveAuth(host, authScheme);
        return this;
    }
Abstract {@link HttpClientContext} builder.

@param <T> The HttpClientContext type or subtype.
@since 5.4
httpclient5/src/main/java/org/apache/hc/client5/http/AbstractClientContextBuilder.java