Twitter were the first to get the future/promise abstraction right and publish it widely (in Finagle). That inspired not just Scala's now-standard Futures but also the CompletableFuture in newer versions of Java and even e.g. Rust's Future, although none of them have the wonderful for/yield syntax (similar to Haskell do notation) that make it such a joy to work with in Scala.
Sadly most of the tooling funding came from the other big Scala user, who favoured an invisible-yield-point style (which I'm pretty sure inspired the model that Kotlin now uses with suspend functions).
One of the many tragedies of Scala (still the best general-purpose language on the whole, IMO) is that the community formed these somewhat siloed ecosystems that were each doing things their own way and had their own stack of libraries that didn't really play nice with each other. The language actually makes it very easy to write your own adapters (which may be why industrial users didn't create a lot of pressure to stop all the nonsense), but political fallings-out usually meant that it took years before there were "blessed"/official ways to use X with Y.
Sadly most of the tooling funding came from the other big Scala user, who favoured an invisible-yield-point style (which I'm pretty sure inspired the model that Kotlin now uses with suspend functions).
One of the many tragedies of Scala (still the best general-purpose language on the whole, IMO) is that the community formed these somewhat siloed ecosystems that were each doing things their own way and had their own stack of libraries that didn't really play nice with each other. The language actually makes it very easy to write your own adapters (which may be why industrial users didn't create a lot of pressure to stop all the nonsense), but political fallings-out usually meant that it took years before there were "blessed"/official ways to use X with Y.