Exporter Pushgateway runtime issue in versions 1.3.4 and above

Version 1.3.3 works correctly
I believe it is caused by https://github.com/prometheus/client_java/pull/1190
I am using default format in pushgateway which I think is protobuf.

Dependencies in pom.xml:

<dependency>
  <groupId>io.prometheus</groupId>
  <artifactId>prometheus-metrics-core</artifactId>
  <version>1.3.4</version>
</dependency>
<dependency>
  <groupId>io.prometheus</groupId>
  <artifactId>prometheus-metrics-exporter-pushgateway</artifactId>
  <version>1.3.4</version>
</dependency>

Runtime issue from shaded jar:

Exception in thread (...) java.lang.ExceptionInInitializerError
Caused by: java.lang.RuntimeException: class io.prometheus.metrics.expositionformats.PrometheusProtobufWriter is not available
at io.prometheus.metrics.exporter.pushgateway.PushGateway.<init>(PushGateway.java:99)
at io.prometheus.metrics.exporter.pushgateway.PushGateway.<init>(PushGateway.java:77)
at io.prometheus.metrics.exporter.pushgateway.PushGateway$Builder.build(PushGateway.java:456)
(...)
Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.RuntimeException: class io.prometheus.metrics.expositionformats.PrometheusProtobufWriter is not available

So I guess it complains about
https://github.com/prometheus/client_java/blob/main/prometheus-metrics-exporter-pushgateway/src/main/java/io/prometheus/metrics/exporter/pushgateway/PushGateway.java#L9
or
https://github.com/prometheus/client_java/blob/main/prometheus-metrics-exporter-pushgateway/src/main/java/io/prometheus/metrics/exporter/pushgateway/PushGateway.java#L114

Confronta il comportamento delle dipendenze di 1.3.3 e 1.3.4 in pom.xml, quindi ispeziona PushGateway.java intorno alle righe indicate e il packaging dello shaded-jar. Ricostruisci il motivo per cui PrometheusProtobufWriter non è disponibile a runtime e conferma che il formato Pushgateway predefinito venga inizializzato correttamente in uno shaded jar.