两个一致的调用导致错误-收到错误代码为2的RST_STREAM

Question

我使用Swift 5.0代码中的Objective-C gRPC库（版本1.24.2） 我在iOS 12.2上运行代码。

服务器是在grpc-go v1.19.0上编写的

我的原型：

syntax = "proto3";
package ...;

message Response {
    ServiceStatus status = 1;
}

message ResultStatus {
    Status status = 1;
}

enum Status {
    OK = 0;
    ...
}

syntax = "proto3";
package ...;

message Feature {
    string name = 1;
    bool is_enabled = 2;
    int64 valid_until = 3;
}

message QueryFeatures {
}

message ResultFeature {
    common.ResultStatus status = 1;
    repeated Feature features = 2;
    reserved 3;
}

service FeatureTogglingService {
    rpc GetFeatures(QueryFeatures) returns (ResultFeature);
}

syntax = "proto3";
package ...;

message CommandSendOnlineStatus {

}

service UserService {
    rpc SendOnlineStatus(CommandSendOnlineStatus) returns (Response);
}

我做了什么？

我有一个符合GRPCProtoResponseHandler协议的类，它有一个方法foo，该方法创建两个服务并从每个服务中调用一个方法：

class MyClass: NSObject, GRPCProtoResponseHandler {
    var dispatchQueue: DispatchQueue {
        return .main
    }

    func foo() {
        let callOptions = GRPCMutableCallOptions()
        callOptions.initialMetadata = ["authorization": "Bearer eyJhbGciO..."]

        featureService = FeatureTogglingService(host: "example.com:443", callOptions: callOptions)
        userService = UserService(host: "example.com:443", callOptions: callOptions)

        let userCall = userService?.sendOnlineStatus(withMessage: userRequest, responseHandler: self, callOptions: nil)
        let featureCall = featureService?.getFeaturesWithMessage(featureTogglingRequest, responseHandler: self, callOptions: nil)
        featureCall?.start()
        userCall?.start()
    }

    func didReceiveProtoMessage(_ message: GPBMessage?) {
    }

    func didClose(withTrailingMetadata trailingMetadata: [AnyHashable : Any]?, error: Error?) {
        print("??? error: \(error)")
    }
}

我调用foo方法。

我期望看到什么？

我希望看到两次用func didClose(withTrailingMetadata trailingMetadata: [AnyHashable : Any]?, error: Error?)调用方法error == nil

相反，我看到了什么？

我看到两次调用方法func didClose(withTrailingMetadata trailingMetadata: [AnyHashable : Any]?, error: Error?)，其中error包含：

??? error: Optional(Error Domain=io.grpc Code=13 "{"created":"@1572546519.322425000","description":"Error received from peer ipv4:...:443","file":".../Pods/gRPC-Core/src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Received RST_STREAM with error code 2","grpc_status":13}" UserInfo={io.grpc.HeadersKey={
    date = "Thu, 31 Oct 2019 18:28:39 GMT";
    server = nginx;
}, io.grpc.TrailersKey={
}, NSDebugDescription={"created":"@1572546519.322425000","description":"Error received from peer ipv4:...:443","file":".../Pods/gRPC-Core/src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Received RST_STREAM with error code 2","grpc_status":13}, NSLocalizedDescription=Received RST_STREAM with error code 2})
??? error: Optional(Error Domain=io.grpc Code=13 "{"created":"@1572546519.322339000","description":"Error received from peer ipv4:...:443","file":".../Pods/gRPC-Core/src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Received RST_STREAM with error code 2","grpc_status":13}" UserInfo={io.grpc.HeadersKey={
    date = "Thu, 31 Oct 2019 18:28:39 GMT";
    server = nginx;
}, io.grpc.TrailersKey={
}, NSDebugDescription={"created":"@1572546519.322339000","description":"Error received from peer ipv4:...:443","file":".../Pods/gRPC-Core/src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Received RST_STREAM with error code 2","grpc_status":13}, NSLocalizedDescription=Received RST_STREAM with error code 2})

但是在服务器日志中，我看到由于响应状态为200，所以每个调用都正常。这就是为什么我认为gRPC Objective-C库的客户端存在问题。

我做错了什么？