Constant ISSUE_DEPENDENCIES 

pub const ISSUE_DEPENDENCIES: &str = r#"query($id:ID!,$first:Int!,$after:String){node(id:$id){__typename
      ... on Issue{body
        blockedBy(first:$first,after:$after){nodes{...Related}pageInfo{hasNextPage endCursor}}
        blocking(first:$first,after:$after){nodes{...Related}pageInfo{hasNextPage endCursor}}
      }}} fragment Related on Issue{id title body parent{id} subIssuesSummary{total}}"#;

Reads both dependency directions for one issue, with each far end’s own kind — and the issue’s own body, which is where an edge to another source is recorded, so that half of a dependency read needs no second read of the issue or of the board.