pool. Legacy wallets only.
  "keypoolsize" : n,                      (numeric) how many new keys are pre-generated (only counts external keys)
  "keypoolsize_hd_internal" : n,          (numeric, optional) how many new keys are pre-generated for internal use (used for change outputs, only appears if the wallet is using this feature, otherwise external keys are used)
  "unlocked_until" : xxx,                 (numeric, optional) the UNIX epoch time until which the wallet is unlocked for transfers, or 0 if the 