Event Markers in Blazor Gantt Chart component

@using Syncfusion.Blazor.Gantt
<SfGantt DataSource="@TaskCollection" Height="450px" Width="700px">
    <GanttTaskFields Id="TaskId" Name="TaskName" StartDate="StartDate" EndDate="EndDate"
            Duration="Duration" Progress="Progress" Child="SubTasks">
    </GanttTaskFields>
    <GanttEventMarkers>
        <GanttEventMarker Day="@Event" Label="Project approval and kick-off"
            CssClass="e-custom-event-marker"></GanttEventMarker>
    </GanttEventMarkers>
</SfGantt>

@code{
    public DateTime Event = new DateTime(2019, 04, 11);
    public List<TaskData> TaskCollection { get; set; }
    protected override void OnInitialized()
    {
        this.TaskCollection = GetTaskCollection();
    }

    public class TaskData
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }
        public string Duration { get; set; }
        public int Progress { get; set; }
        public List<TaskData> SubTasks { get; set; }
    }

    public static List <TaskData> GetTaskCollection() {
    List <TaskData> Tasks = new List <TaskData> () {
        new TaskData() {
            TaskId = 1,
            TaskName = "Project initiation",
            StartDate = new DateTime(2019, 04, 02),
            EndDate = new DateTime(2019, 04, 21),
            SubTasks = (new List <TaskData> () {
                new TaskData() {
                    TaskId = 2,
                    TaskName = "Identify Site location",
                    StartDate = new DateTime(2019, 04, 02),
                    Duration = "0",
                    Progress = 30,
                },
                new TaskData() {
                    TaskId = 3,
                    TaskName = "Perform soil test",
                    StartDate = new DateTime(2019, 04, 02),
                    Duration = "4",
                    Progress = 40,
                },
                new TaskData() {
                    TaskId = 4,
                    TaskName = "Soil test approval",
                    StartDate = new DateTime(2019, 04, 02),
                    Duration = "0",
                    Progress = 30,
                },
            })
        },
        new TaskData() {
            TaskId = 5,
            TaskName = "Project estimation",
            StartDate = new DateTime(2019, 04, 02),
            EndDate = new DateTime(2019, 04, 21),
            SubTasks = (new List <TaskData> () {
                new TaskData() {
                    TaskId = 6,
                    TaskName = "Develop floor plan for estimation",
                    StartDate = new DateTime(2019, 04, 04),
                    Duration = "3",
                    Progress = 30,
                },
                new TaskData() {
                    TaskId = 7,
                    TaskName = "List materials",
                    StartDate = new DateTime(2019, 04, 04),
                    Duration = "3",
                    Progress = 40,
                },
                new TaskData() {
                    TaskId = 8,
                    TaskName = "Estimation approval",
                    StartDate = new DateTime(2019, 04, 04),
                    Duration = "0",
                    Progress = 30
                }
            })
        }
    };

    return Tasks;
}
}
<style>
    .e-gantt .e-gantt-chart .e-custom-event-marker {
        width: 1px;
        border-left: 2px red dotted;
    }
</style>