Clarify that ngtcp2_crypto_aead_max_overhead does not use max_overhead field
@@ -114,7 +114,10 @@ ngtcp2_crypto_aead_noncelen(const ngtcp2_crypto_aead *aead);
* @function
*
* `ngtcp2_crypto_aead_max_overhead` returns the maximum authenticated
- * encryption overhead of |aead|.
+ * encryption overhead of |aead|. This function does not use
+ * :member:`ngtcp2_crypto_aead.max_overhead`. Instead, it queries the
+ * length to an underlying TLS backend with
+ * :member:`ngtcp2_crypto_aead.native_handle`.
*/
NGTCP2_EXTERN size_t
ngtcp2_crypto_aead_max_overhead(const ngtcp2_crypto_aead *aead);
