Count the external (receiving) keys available in the keypool.
Declared in <wallet/wallet.h>
[[requires_capability(0x7fbc76bfdb78), requires_capability(0x7fbc81b77538), requires_capability(0x7fbc7e0153b8), requires_capability(0x7fbc7e244868), requires_capability(0x7fbc8e7154a8)]]
size_t
KeypoolCountExternalKeys() const;
The number of external keys in the keypool.