@UnstableApi
    default ExchangeType exchangeType(RoutingContext routingContext) {
        return ExchangeType.BIDI_STREAMING;
    }
Determines an {@link ExchangeType} for this {@link HttpService} from the given {@link RoutingContext}.
By default, {@link ExchangeType#BIDI_STREAMING} is set.

<p>Note that an {@link HttpRequest} will be aggregated before serving the {@link HttpService} if
{@link ExchangeType#UNARY} or {@link ExchangeType#RESPONSE_STREAMING} is set.
core/src/main/java/com/linecorp/armeria/server/HttpService.java