@Override public BraveScope activate(Span span, boolean finishSpanOnClose) { if (span == null) return null; if (!(span instanceof BraveSpan)) { throw new IllegalArgumentException( "Span must be an instance of brave.opentracing.BraveSpan, but was " + span.getClass()); } return newScope((BraveSpan) span, finishSpanOnClose); }