remove async arg

[SylvainJuge]

Follow-up of #193 , the async parameter was removed, but the HandleStream interface was not updated to reflect this.

This currently prevents updating apm-data version used in apm-server.

Once this is merged elastic/apm-server#12386 will be unblocked and must have its version of apm-data updated.

[simitt]

Apologies for this oversight, and thanks for contributing the fix.

[SylvainJuge]

Thanks @simitt for the review, can we merge this now ?

As a follow-up we should probably set-up a CI job that ensures apm-server main branch is tested with the current state of apm-data main branch, or 100x better an automatic PR is created to update apm-data in apm-server so we have feedback when changes merged in apm-data break something. Given we expect contributions from outside of the apm-server team this is quite likely to happen (my future self is the one that is likely to make this kind of oversight).

[simitt]

or 100x better an automatic PR is created to update apm-data in apm-server so we have feedback when changes merged in apm-data break something

agreed; created elastic/apm-server#12268 recently