title: Unexpected call to mock ( gomock) gRPC
body: <p>I have gRPC service (say svc1) which invokes another gRPC service, using its gRPC stub (say svc2_client).</p>
  <p>I have generated the client mock for svc2_client. Unit tests as per documentation are working fine, i.e. svc2_client is tested using the generated mock.</p>
  <p>However, I have svc1 as shown below:</p>
  <pre><code>// Synonymous to proto service generated.
  type Svc1 struct {
      rt svc2pb.Svc2Client
  }
  
  // Constructor to get Service.
  func NewSvc1(rt svc2pb.Svc2Client) *Svc1 {
      return &amp;Svc1{rt}
  }
  ...
  ...
  </code></pre>
  <p><strong>Expected behavior</strong>: <br>
  Expecting it to succeed</p>
  <p><strong>To Reproduce</strong> <br>
  Steps to reproduce the behavior:</p>
  <p>Returns an error:</p>
  <pre><code>=== RUN   TestMethod1Svc1
  
      TestMethod1Svc1: svc1.go:40: Unexpected call to *mock_svc2client.MockSvc2Client.Method1([context.Background.WithDeadline(2020-06-22 10:14:25.620736 +0530 IST m=+3.002262784 [2.999757626s]) key1:&quot;1&quot;  } ]) at ...server/mocks/svc2client_mock.go:65 because: there are no expected calls of the method &quot;Method1&quot; for that receiver
  --- FAIL: TestMethod1Svc1 (0.00s)
  
  </code></pre>
  <p>Newbie in Go, could you help me out here.</p>
  <p>Additional Information:</p>
  <ul>
  <li>gomock mode (source): source</li>
  <li>gomock version or git ref: github.com/golang/mock v1.4.3</li>
  <li>golang version: go version go1.14 darwin/amd64</li>
  </ul>