panic: runtime error: index out of range

1: running [Created by grpc.(*Server).serveStreams.func1 @ server.go:324]
                   panic.go:464            panic(0x163f3a0, 0xc820012030)
    roachpb        data.pb.go:1208         encodeVarintData(#9, 0x3, 0x3, 0x3, 0, 0x2)
    roachpb        data.pb.go:601          (*Timestamp).MarshalTo(0xc82a32ab18, #9, 0x3, 0x3, 0x4, 0, 0)
    roachpb        api.pb.go:3882          (*BatchResponse_Header).MarshalTo(#11, 0xc827b210e3, 0x103, 0x103, 0x103, 0, 0)
    roachpb        api.pb.go:3808          (*BatchResponse).MarshalTo(#11, #8, 0x106, 0x106, 0x106, 0, 0)
    roachpb        api.pb.go:3793          (*BatchResponse).Marshal(#11, #8, 0x106, 0x106, 0, 0)
    proto          encode.go:225           Marshal(0x7f83ed211aa8, #11, 0, 0, 0, 0, 0)
    grpc           rpc_util.go:70          protoCodec.Marshal(#1, #11, 0, 0, 0, 0, 0)
    grpc           <autogenerated>:18      (*protoCodec).Marshal(#3, #1, #11, 0, 0, 0, 0, 0)
    grpc           rpc_util.go:248         encode(#13, #3, #1, #11, 0, 0, 0, 0, 0, 0, ...)
    grpc           server.go:412           (*Server).sendResponse(#4, #12, #5, #10, #1, #11, 0, 0, 0xc82e5a0f10, 0, ...)
    grpc           server.go:526           (*Server).processUnaryRPC(#4, #12, #5, #10, #6, #2, 0, 0, 0)
    grpc           server.go:646           (*Server).handleStream(#4, #12, #5, #10, 0)
    grpc           server.go:323           (*Server).serveStreams.func1.1(#7, #4, #12, #5, #10)