This week's All Star Game was the final test run of video review before Major League Soccer implements Video Assistant Referee in a competitive environment this weekend. MLS joins the Autralian A-League as the first top flight leagues to trial the system, having held an offline trial since the start of the year. The German Bundesliga and Italy's Serie A will both adopt the technology when their seasons commence in two weeks time. If you have an hour to spare, I would highly recommend watching the VAR seminar hosted by former Premier League referee, Howard Webb.

If you don't have an hour , but perhaps two minutes, we have a simple walkthrough of the incident in Montreal, where Christian Colman appeared to score his first MLS goal.

Colman's shot has been cleared by Daniel Lovitz, but there is a huge degree of difficulty to make a split second decision over a matter of inches, while the linesman is running back. In this case, referee Robert Sibigia allows play to continue, given that his position would make it impossible to see and his AR does not see anything compelling enough to signal a clear goal, and the ball immediately goes out of play for a corner.

While we are watching Ryan Hollingshead and Roland Lamah protest what they saw, the Video Assistant Referee is performing a "check" from the start of the Attacking Phase of Play. This is the first forward motion to start off the attack, Carlos Gruezo's short free kick. The Assistant Video Assistant Referee will now be in contact with the broadcaster and officials, as well as looking at the current feed in case there is further incident during the stoppage. This process has to be completed before the ball returns to play, so the referee can hold up the corner by placing one hand out, with a finger to his earpiece. In the video we looked at possible offside, fouls, and whether the ball actually crossed the line. The VAR is attempting to find anything in the phase of play that would negate or confirm the goal. Our check took 34 seconds to show the ball was a few inches over the line without any illegality in the play. At this point, the VAR will suggest that the referee "reviews" the play, or for a clear and obvious error like a mistaken identity, will simply say where the mistake was made and the correct solution, to avoid additional delay.

We are fortunate in this instance that the angles are good enough to demonstrate the ball position. If the camera was placed a few feet further up the field, the officials would lack any evidence to justify awarding a goal. The system won't be foolproof, and changes are likely to be needed on the back of it, such as visual aids for judging the line of offside.

With the suggestion that the referee should review the footage, the referee will then make a gesture in the shape of a TV screen and go to the sideline to be shown the evidence. The final call will always remain with the match referee, who can disagree with the VAR's opinion on the check, or simply opt not to review the play.

There was an incident in the 4-0 loss to Vancouver where I wonder how that last sentence would have factored. Baldomero Toledo awarded a penalty for a Kellyn Acosta foul on Fredy Montero. Toledo was asked for his opinion on the play after the game:

"Although no. 23, Acosta, did make contact with the ball, he charged no. 12, Montero, in a careless manner inside the penalty area and disallowed no. 12 an opportunity to play the ball. This warranted the penalty kick."

Here is the incident, which does not resemble Toledo's recollection:

For this to be overturned, Toledo would have to be willing to review the play, and also willing to accept that he made a mistake on a 50-50 ball where Matt Hedges was always favorite to clear the resulting ball. Toledo has gained his reputation throughout MLS as 'The Toledo Show' by being brazen through some questionable decisions. People make mistakes, but the system relies on the humility to publicly acknowledge that a mistake was made, in an environment where officials aren't typically held accountable for mistakes. The VAR system is not designed to create perfect officiating, and officials will vary in their use of the system, just as they do with how generous they are with advantage, or how much leeway they give on persistent infringement.

We all hold our own mini-reviews as fans of the game. When Carlos Gruezo saw red, and you saw the GIFs posted of the Ecuadorean midfielder swinging his elbow, you felt an acceptance. Likewise when Lamah appeared to equalize, only for the replay to show him offside. We get the benefit of these additional angles very quickly, and reserve our right to judge officials based on having a greater range of vantages, so it is only fair to afford them the same opportunity in those key moments.