PubSubIO.WriteParam isn't inferred correctly in IntelliJ for subtypes

[kellen]

e.g. when using:

val scoll: SCollection[MyMessage] = ???
scoll.write(PubsubIO.proto[MyMessage](topic))(PubsubIO.WriteParam())

IntelliJ will infer Nothing as the type for the second argument to write. Not sure how/if this is possible to fix on our side.