Clarify the return value of ngtcp2_conn_write_connection_close variants
@@ -4254,6 +4254,9 @@ NGTCP2_EXTERN ngtcp2_ssize ngtcp2_conn_writev_datagram_versioned(
* close. We may change this behaviour in the future to allow
* graceful shutdown.
*
+ * This function returns the number of bytes written in |dest| if it
+ * succeeds, or one of the following negative error codes:
+ *
* :macro:`NGTCP2_ERR_NOMEM`
* Out of memory
* :macro:`NGTCP2_ERR_NOBUF`
@@ -4300,6 +4303,9 @@ NGTCP2_EXTERN ngtcp2_ssize ngtcp2_conn_write_connection_close_versioned(
* close. We may change this behaviour in the future to allow
* graceful shutdown.
*
+ * This function returns the number of bytes written in |dest| if it
+ * succeeds, or one of the following negative error codes:
+ *
* :macro:`NGTCP2_ERR_NOMEM`
* Out of memory
* :macro:`NGTCP2_ERR_NOBUF`
@@ -4977,6 +4983,9 @@ NGTCP2_EXTERN void ngtcp2_connection_close_error_set_application_error(
* close. We may change this behaviour in the future to allow
* graceful shutdown.
*
+ * This function returns the number of bytes written in |dest| if it
+ * succeeds, or one of the following negative error codes:
+ *
* :macro:`NGTCP2_ERR_NOMEM`
* Out of memory
* :macro:`NGTCP2_ERR_NOBUF`
