I have this error when using the php http module.

http_send_content_disposition('a.pdf', true);
http_send_content_type("application/x-octetstream");
http_throttle(0.1, 40480);
http_send_file('/pathtopdf/a.pdf'));

Any help? Is there a way to increase the memory?

Tried to add

push_stream_shared_memory_size 64M; in the conf file but I get

unknown directive "push_stream_shared_memory_size" in /etc/nginx/nginx.conf:40