extend type Query {
    posts(streamID: String! paging: PageInput): Connection!
}
extend type Subscription {
    """after == 0 start from begining, after == -1 start from end"""
    postAdded(streamID: String! after: Int! = -1): PostEvent
}
type PostEvent implements Edge {
    id: ID!

    payload: String!
    payloadJSON: Map!
    tags: [String!]!

    meta: Meta!
}