sodium_crypto_aead_xchacha20poly1305_ietf_keygen — Generate a random XChaCha20-Poly1305 key.
Generate a random key for use with sodium_crypto_aead_xchacha20poly1305_ietf_encrypt() and sodium_crypto_aead_xchacha20poly1305_ietf_decrypt().
This function has no parameters.
Returns a 256-bit random key.