Looks like the 'defaults' option doesn't work in grpc proto-loader's

[lidongze0629]

Following the mocking grpc doc, I have the following config

#  cat plconfig.js
module.exports.plconfig = {
    keepCase: true,
    defaults: true,
    arrays: true,
    objects: true,
    includeDirs: [
        "./grpc/protos"
    ],
}

# cat grpc/streamCall.mock
{
    "data": {
        "header": {
            "finished": false,
            "index": 0
    },
    "end": {
        "header": {
            "finished": true,
            "index": 1
    }
}

But the index: 0 and finished: false from data filed can't display in my terminal response; Could someone can help me? thanks.