How to send request to API that uses MessagePack with MagicOnion using Postman

I have an API that is using MagicOnion and MessagePack in .NET. I am using swagger like this:

public static IServiceCollection AddMagicOnionServices(this IServiceCollection services)
{
    services.AddMagicOnion();
    MessagePackSerializer.DefaultOptions =
        MessagePackSerializerOptions.Standard.WithResolver(
            CompositeResolver.Create(
                ContractlessStandardResolver.Instance,
                StandardResolver.Instance));

    services.AddApiVersioning(o =>
    {
        o.DefaultApiVersion = new ApiVersion(1, 0);
        o.AssumeDefaultVersionWhenUnspecified = false;
        o.RouteConstraintName = "apiVersion";
        o.ApiVersionReader = new UrlSegmentApiVersionReader();
        o.ReportApiVersions = true;
    })
    .AddMvc()
    .AddApiExplorer(
        o =>
        {
            // ReSharper disable once StringLiteralTypo
            o.GroupNameFormat = "'v'VVV";
            o.SubstituteApiVersionInUrl = true;
        });

    services.AddSwaggerGen(
        options =>
        {
            options.AddEnumsWithValuesFixFilters().EnableAnnotations(true, true);

            if (Assembly.GetExecutingAssembly().Location is { } location)
            {
                options.IncludeXmlComments(Path.ChangeExtension(location, ".xml"));
                options.IncludeGrpcXmlComments(Path.ChangeExtension(location, ".xml"), true);
            }
        });

    return services;
}

public static void UseAppSwagger(this WebApplication app)
{
    app.UseSwagger(o => o.RouteTemplate = "/swagger-rest/{documentName}/swagger.json");
    app.UseSwaggerUI(o => o.RoutePrefix = "swagger-rest");
}

I am able to open swagger and send requests :

But how to import it or use endpoints from Postman? Before when API was using protobuf instead of MessagePack, I was able to import protobufs in postman and send request using Grpc