@Override
    public StartMatchBackfillResult startMatchBackfill(StartMatchBackfillRequest request) {
        request = beforeClientExecution(request);
        return executeStartMatchBackfill(request);
    }
<p>
Finds new players to fill open slots in currently running game sessions. The backfill match process is
essentially identical to the process of forming new matches. Backfill requests use the same matchmaker that was
used to make the original match, and they provide matchmaking data for all players currently in the game session.
FlexMatch uses this information to select new players so that backfilled match continues to meet the original
match requirements.
</p>
<p>
When using FlexMatch with Amazon GameLift managed hosting, you can request a backfill match from a client service
by calling this operation with a <code>GameSessions</code> ID. You also have the option of making backfill
requests directly from your game server. In response to a request, FlexMatch creates player sessions for the new
players, updates the <code>GameSession</code> resource, and sends updated matchmaking data to the game server.
You can request a backfill match at any point after a game session is started. Each game session can have only
one active backfill request at a time; a subsequent request automatically replaces the earlier request.
</p>
<p>
When using FlexMatch as a standalone component, request a backfill match by calling this operation without a game
session identifier. As with newly formed matches, matchmaking results are returned in a matchmaking event so that
your game can update the game session that is being backfilled.
</p>
<p>
To request a backfill match, specify a unique ticket ID, the original matchmaking configuration, and matchmaking
data for all current players in the game session being backfilled. Optionally, specify the
<code>GameSession</code> ARN. If successful, a match backfill ticket is created and returned with status set to
QUEUED. Track the status of backfill tickets using the same method for tracking tickets for new matches.
</p>
<p>
Only game sessions created by FlexMatch are supported for match backfill.
</p>
<p>
<b>Learn more</b>
</p>
<p>
<a href="https://docs.aws.amazon.com/gamelift/latest/flexmatchguide/match-backfill.html"> Backfill existing games
with FlexMatch</a>
</p>
<p>
<a href="https://docs.aws.amazon.com/gamelift/latest/flexmatchguide/match-events.html"> Matchmaking events</a>
(reference)
</p>
<p>
<a href="https://docs.aws.amazon.com/gamelift/latest/flexmatchguide/gamelift-match.html"> How Amazon GameLift
FlexMatch works</a>
</p>

@param startMatchBackfillRequest
@return Result of the StartMatchBackfill operation returned by the service.
@throws InvalidRequestException
        One or more parameter values in the request are invalid. Correct the invalid parameter values before
        retrying.
@throws NotFoundException
        THe requested resources was not found. The resource was either not created yet or deleted.
@throws InternalServiceException
        The service encountered an unrecoverable internal failure while processing the request. Clients can retry
        such requests immediately or after a waiting period.
@throws UnsupportedRegionException
        The requested operation is not supported in the Region specified.
@sample AmazonGameLift.StartMatchBackfill
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/gamelift-2015-10-01/StartMatchBackfill" target="_top">AWS
     API Documentation</a>
aws-java-sdk-gamelift/src/main/java/com/amazonaws/services/gamelift/AmazonGameLiftClient.java