public static function startSpan(array $spanOptions = [])
    {
        if (!isset(self::$instance)) {
            return new Span();
        }
        return self::$instance->startSpan($spanOptions);
    }
public static function startSpan(array $spanOptions = [])
    {
        if (!isset(self::$instance)) {
            return new Span();
        }
        return self::$instance->startSpan($spanOptions);
    }
public static function startSpan ( array $ spanOptions = [ ] ) { if ( ! isset ( self :: $ instance ) ) { return new Span ( ) ; } return self :: $ instance -> startSpan ( $ spanOptions ) ; }
Explicitly start a new Span. You will need to attach the span and handle
any thrown exceptions.

Example:
```
$span = Tracer::startSpan(['name' => 'expensive-operation']);
$scope = Tracer::withSpan($span);
try {
// do something expensive
} catch (\Exception $e) {
} finally {
$scope->close();
}
```

@param array $spanOptions [optional] Options for the span. See
<a href="Span.html#method___construct">OpenCensus\Trace\Span::__construct()</a>
@return Span
Explicitly start a new Span . You will need to attach the span and handle any thrown exceptions .