static Runnable withSpan(Span span, boolean endSpan, Runnable runnable) {
    return new RunnableInSpan(span, runnable, endSpan);
  }
static Runnable withSpan ( Span span , boolean endSpan , Runnable runnable ) { return new RunnableInSpan ( span , runnable , endSpan ) ; }
Wraps a {@link Runnable} so that it executes with the {@code span} as the current {@code Span}.

@param span the {@code Span} to be set as current.
@param endSpan if {@code true} the returned {@code Runnable} will close the {@code Span}.
@param runnable the {@code Runnable} to run in the {@code Span}.
@return the wrapped {@code Runnable}.