anchor.diff:  open MBrace.Azure.Runtime.Utilities
   open MBrace.Runtime
   
  -type WorkerRecord(pk, id) =
  -    inherit TableEntity(pk, id)
  +[<AllowNullLiteral()>]
  +type WorkerRecord(partitionKey, id) =
  +    inherit TableEntity(partitionKey, id)
       
       member val Id                 = id with get, set
       member val Hostname           = Unchecked.defaultof<string> with get, set
  
positive.code:         member this.GetAvailableWorkers(): Async<WorkerState []> = 
              async { 
                  let! workers = this.GetAllWorkers()
                  return workers |> Array.filter (fun w -> DateTime.UtcNow - w.LastHeartbeat <= maxHeartbeatTimespan)
              }
          
          member this.SubmitPerformanceMetrics(id: IWorkerId, perf: Utils.PerformanceMonitor.PerformanceInfo): Async<unit> = 
  
negative.code:             let! records = Table.queryPK<WorkerRecord> config table partitionKey
              let state = records |> Array.map mkWorkerState
              return state
          }
  
      member this.UnsubscribeWorker(id : IWorkerId) =
          async {
              let record = new WorkerRecord(partitionKey, id.Id)
              return! Table.delete config table record
          }
  
      interface IWorkerManager with
  