QUIC: allowed ngx_quic_frame_sendto() to return NGX_AGAIN. Previously, NGX_AGAIN returned by ngx_quic_send() was treated by ngx_quic_frame_sendto() as error, which triggered errors in its callers. However, a blocked socket is not an error. Now NGX_AGAIN is passed as is to the ngx_quic_frame_sendto() callers, which can safely ignore it.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have