Span created to auto-dispose is generating WARN when manually closed

From gitter channel:

rwkarg @rwkarg 09:49
We're getting WARN logs from OpenTracing spans for dispatch_to_server spans because they're created with StartActive(finishOnDispose:true) (this is the default value, it's actually started with StartActive() ) but then they manually have Finish called and later it tries to get finished again on dispose:
2019-03-29 16:37:46.1887 WARN Jaeger.Tracer Span has already been finished; will not be reported again. Operation: dispatch_to_server Trace Id: 461c320f780a8709 Span Id: c564c068ac508c61
The log line is from the Jaeger reporter of the OpenTracing span but it is a valid warning. If the intention is to manually call Finish on the span (which appears to be what is intended), then the span needs to be started with StartActive(finishOnDispose:false)
This isn't causing any errors but we're getting a WARN log line for every operation that executes

Details on where issue is located:

Here's where the span is built for the dispatch_to_server span:
https://github.com/couchbase/couchbase-net-client/blob/master/src/Couchbase/Core/Diagnostics/Tracing/TracerExtensions.cs#L97