Trigger to to Send a slack message

Question

I am working on a solution to send a message to a Slack channel when a user creates a record on Salesforce. I have gone through Apex SDK for Slack App and managed to connect the app with Salesforce.

I want to create a trigger on Salesforce so that, when a user creates a record, it will invoke Slack.ActionDispatcher class:

/*
    This example apex class extends Slack.ActionDispatcher and is responsible for
    responding to the "onsubmit" event defined in the 'view_opportuniy', 'view_account',
    and 'view_contact' view.
*/
public class ActionDispatcherPostRecordDetailMessage extends Slack.ActionDispatcher {
    
    public override Slack.ActionHandler invoke(Map<String, Object> parameters, Slack.RequestContext context) {
        return Slack.ActionHandler.ack(new Handler(parameters, context));
    }

    public class Handler implements Slack.RunnableHandler {
        Map<String, Object> parameters;
        Slack.RequestContext context;

        public Handler(Map<String, Object> parameters, Slack.RequestContext context) {
            this.parameters = parameters;
            this.context = context;
        }

        public void run() {
            Slack.App app = Slack.App.ApexSlackApp.get();
            Slack.UserClient userClient = app.getUserClientForTeam(this.context.getTeamId(), this.context.getUserId());

            String recordId = (String) this.parameters.get('recordId');
            String objectApiName = (String) this.parameters.get('objectApiName');

            Slack.ViewReference viewReference = Slack.View.record_detail_message.get();
            viewReference.setParameter('headerText', objectApiName + ' Record Details');
            viewReference.setParameter('recordId', recordId);
            viewReference.setParameter('objectApiName', objectApiName);

            Slack.ChatPostMessageRequest req = new Slack.ChatPostMessageRequest.builder()
                .channel((String) this.parameters.get('channelId'))
                //TODO should text be required if you are setting a view reference?
                .text('Details for record id' + recordId)
                .viewReference(viewReference)
                .build();

            Slack.ChatPostMessageResponse response = userClient.ChatPostMessage(req);
            if (response.getError() != null) {
                System.debug(response.getResponseMetadata().getMessages());
            }
        }
    }
}

This is my trigger:

public static void handleOpportunity(List<Opportunity> newOpportunities) {
        for (Opportunity opp : newOpportunities) {
            
            ActionDispatcherPostRecordDetailMessage.Handler handler = new ActionDispatcherPostRecordDetailMessage.Handler(
                new Map<String, Object>{
                    'recordId' => opp.Id,
                        'objectApiName' => 'Opportunity',
                        'channelId' => 'your_slack_channel_id_here'
                        },
                new Slack.RequestContext() 
            );
            
            
            handler.run();
        }
    } 

In the trigger I get a Method is not visible: void Slack.RequestContext.<init>() error

I am expecting that, when a user creates a record, a Slack message is sent to a channel with the details of the record. After the record is in the channel, I will user a block it to update the record in Salesforce.