diff --git a/call.go b/call.go
index 9d815af..89d2782 100644
--- a/call.go
+++ b/call.go
@@ -40,7 +40,6 @@
 	"golang.org/x/net/context"
 	"golang.org/x/net/trace"
 	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/transport"
 )
 
@@ -94,14 +93,6 @@
 	return stream, nil
 }
 
-// callInfo contains all related configuration and information about an RPC.
-type callInfo struct {
-	failFast  bool
-	headerMD  metadata.MD
-	trailerMD metadata.MD
-	traceInfo traceInfo // in trace.go
-}
-
 // Invoke is called by the generated code. It sends the RPC request on the
 // wire and returns after response is received.
 func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (err error) {
diff --git a/rpc_util.go b/rpc_util.go
index 46a6801..e6b2236 100644
--- a/rpc_util.go
+++ b/rpc_util.go
@@ -75,6 +75,14 @@
 	return "proto"
 }
 
+// callInfo contains all related configuration and information about an RPC.
+type callInfo struct {
+	failFast  bool
+	headerMD  metadata.MD
+	trailerMD metadata.MD
+	traceInfo traceInfo // in trace.go
+}
+
 // CallOption configures a Call before it starts or extracts information from
 // a Call after it completes.
 type CallOption interface {