sendIntegrationMessage

JSlackAttachment att1;
att1.pretext = "Optional text that appears above the attachment block";
att1.title = "This is an example of attachment ...";
att1.text = "*Bold* ~strike~ text";
att1.color = "#4286f4";
JSlackAttachment att2;
att2.title = "This is an example of attachment with code.";
att2.text = "'var i = 0; doSomethingWith(i);'";
att2.color = "#f45641";
JSlackMessage message;
message.channel = "C94S1U658";
message.text = "Test slack message with attachment...";
message.attachments = {att1, att2};
return sendIntegrationMessage("SLACK", message);