@Override
    public Builder decode404() {
      this.decode404 = true;
      return this;
    }
This flag indicates that the {@link #decoder(Decoder) decoder} should process responses with
404 status, specifically returning null or empty instead of throwing {@link FeignException}.

<p>All first-party (ex gson) decoders return well-known empty values defined by {@link
Util#emptyValueOf}. To customize further, wrap an existing {@link #decoder(Decoder) decoder}
or make your own.

<p>This flag only works with 404, as opposed to all or arbitrary status codes. This was an
explicit decision: 404 - empty is safe, common and doesn't complicate redirection, retry or
fallback policy.

@return this builder
vertx/feign-vertx/src/main/java/feign/VertxFeign.java