public static DnsTextEndpointGroup of(String hostname, Function<byte[], @Nullable Endpoint> mapping) {
        return builder(hostname, mapping).build();
    }
Creates a {@link DnsTextEndpointGroup} that schedules queries on a random {@link EventLoop} from
{@link CommonPools#workerGroup()}.

@param hostname the hostname to query DNS queries for
@param mapping the {@link Function} that maps the content of a {@code TXT} record into
               an {@link Endpoint}. The {@link Function} is expected to return {@code null}
               if the record contains unsupported content.
core/src/main/java/com/linecorp/armeria/client/endpoint/dns/DnsTextEndpointGroup.java