∀ {task : Task (Except Lean.Server.RequestError (ProofWidgets.LazyEncodable Lean.Json))} {cancel : IO Unit}
  {task_1 : Task (Except Lean.Server.RequestError (ProofWidgets.LazyEncodable Lean.Json))} {cancel_1 : IO Unit},
  { task := task, cancel := cancel } = { task := task_1, cancel := cancel_1 } → task = task_1 ∧ cancel = cancel_1