An instance of Aead.
This provides all APIs that start with crypto_aead_chacha20poly1305.
crypto_aead_chacha20poly1305
See https://libsodium.gitbook.io/doc/secret-key_cryptography/aead/chacha20-poly1305/original_chacha20-poly1305_construction
Aead get aeadChaCha20Poly1305;