I have gateway project that send data by in MassTransit, and wait to get the response.

I need to add custom header to the request and get it in the consumer
here the gateway code:

private readonly IRequestClient<TokenContracts.FullRequest<REQ>> _Client;

public GWController(IRequestClient<TokenContracts.FullRequest<REQ>> submitTokenRequestClient)
{
    _Client = submitTokenRequestClient;
}

[HttpPost("REQ")]
public async Task<IActionResult> Validate(TokenContracts.FullRequest<REQ> model)
{
    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    try
    {
        var response = await _Client.GetResponse<TokenContracts.FullResponse<Res>>(model);
           
        if (response?.Message?.Msg?.RcType != 1)
            return BadRequest(response.Message);

        return Accepted(response.Message);
    }
    catch (System.Exception ex)
    {
        return Problem(ex.Message);
    }
}  

How can I send the header and get it in the consumer?

Here is the consumer:

public async Task Consume(ConsumeContext<FullRequest<REQ>> context)
{
    try
    {
        var correlationId = context.Headers.Get<Guid>("aa");
        var req = Encoding.UTF8.GetString((byte[])context.ReceiveContext.GetBody());

        var res = await mediator.Send(context.Message.appData);

        await context.RespondAsync<FullResponse<RES>>(res);

        return;
    }
    catch (BadRequestException ex)
    {
    }
}