SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES

SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES：这个常量定义了libsodium库的秘密流加密法中XChaCha20-Poly1305加密方法对加密后的信息所增加的字节数。

const SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES = 17;