我们可以使用自定义模型类来传递HttpRequestMessage和其他必需的参数，然后将该模型类作为OrchestrationClient.StartNewAsync的输入参数传递。以下是示例代码：

public class HttpRequestModel
{
    public HttpRequestMessage RequestMessage { get; set; }
    public string OtherParameter { get; set; }
}

public static async Task Run(
    [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage req,
    [OrchestrationClient] DurableOrchestrationClient starter
)
{
    var model = new HttpRequestModel
    {
        RequestMessage = req,
        OtherParameter = "some other data"
    };
    string instanceId = await starter.StartNewAsync("OrchestratorFunction", model);
}

[FunctionName("OrchestratorFunction")]
public static async Task OrchestratorFunction(
    [OrchestrationTrigger] DurableOrchestrationContext context
)
{
    var httpRequestModel = context.GetInput();
    var httpRequestMessage = httpRequestModel.RequestMessage;
    // do something with the httpRequestMessage object
}