Access current request context and extract current Span from it.
    :return:
        Return current span associated with the current request context.
        If no request context is present in thread local, or the context
        has no span, return None.

def get_current_span():
    """
    Access current request context and extract current Span from it.
    :return:
        Return current span associated with the current request context.
        If no request context is present in thread local, or the context
        has no span, return None.
    """
    # Check against the old, ScopeManager-less implementation,
    # for backwards compatibility.
    context = RequestContextManager.current_context()
    if context is not None:
        return context.span

    active = opentracing.tracer.scope_manager.active
    return active.span if active else None