@type t() :: %ExMCP.Client.States.Reconnecting{
  attempt_number: pos_integer(),
  backoff_ms: pos_integer(),
  common: ExMCP.Client.States.Common.t(),
  last_server_info: map() | nil,
  last_transport: pid() | nil,
  max_attempts: pos_integer() | :infinity,
  reconnect_timer: reference() | nil
}