Discard unfinished Spans before sending them over to Sentry

[marandaneto]

We need to discard Spans that are unfinished before sending them over to Sentry, the reason is getsentry/develop#274

Relay drops the whole transaction if a single Span is unfinished.

@Tyrrrz @brustolin I believe this is also important for you both

[maciejwalkowiak]

When a parent span is not finished, but his child spans are finished, should the parent be removed with children or just a parent and children should stay?

[marandaneto]

When a parent span is not finished, but his child spans are finished, should the parent be removed with children or just a parent and children should stay?

how is it shown in the UI in such cases? does the transaction still get ingested? does the parentless span gets ingested?