Add grpc compatibility test

common/baderror/grpc.go

@@ -0,0 +1,26 @@
+package baderror
+
+import (
+	"context"
+	"io"
+	"net"
+)
+
+func WrapGRPC(err error) error {
+	// grpc uses stupid internal error types
+	if err == nil {
+		return nil
+	}
+	if Contains(err, "EOF") {
+		return io.EOF
+	}
+	if Contains(err, "Canceled") {
+		return context.Canceled
+	}
+	if Contains(err,
+		"the client connection is closing",
+		"server closed the stream without sending trailers") {
+		return net.ErrClosed
+	}
+	return err
+}