public ValueTask<Field> CreateAsync(
    Interval interval,
    CancellationToken cancellationToken = default(CancellationToken)
)

<DxRichEdit @ref="@richEdit" />

@code {
    DxRichEdit richEdit;
    Document documentAPI;
    @* ... *@
    /* Surround the code that contains an asynchronous operation with a try-catch block to handle
    the OperationCanceledException. This exception is thrown when an asynchronous operation is canceled. */
        try {
            documentAPI = richEdit.DocumentAPI;
            @* ... *@
            // Accesses a header
            Section section = await documentAPI.Sections.GetAsync(0);
            SubDocument header = await section.GetHeaderAsync(HeaderFooterType.Primary, true);
            // Inserts the "PAGE" text in the header
            TextSpan pageNumber = await header.AddTextAsync("PAGE");
            // Creates a PAGE field
            Field pageField = await header.Fields.CreateAsync(pageNumber.Interval);
            // Updates the field
            await header.Fields.UpdateAsync(pageField);
            @* ... *@
        }
        catch (OperationCanceledException e) {
            Console.WriteLine($"{nameof(OperationCanceledException)} thrown with message: {e.Message}");
        }
}