Nginx Connection Reset On Slow Connections

I am getting connection reset with Nginx when the client has a slow connection. This is just a static http website...no back ends. Any ideas how to stop the connection resets on slow connections? I tried playing with the timeout values but haven't found success.

In the log, I see this error:

2015/09/21 17:11:57 [info] 8704#0: *44 client prematurely closed connection while sending response to client

events {
    worker_connections 128;
    use epoll;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    log_format main
        '$remote_addr - $remote_user [$time_local] '
        '"$request" $status $bytes_sent '
        '"$http_referer" "$http_user_agent" '
        '"$gzip_ratio"';

    client_header_timeout 12s;
    client_body_timeout 12s;
    send_timeout 10s;
    keepalive_timeout 15s;

#   open_file_cache max=1s inactive=1s;
#open_file_cache max=500 inactive=600s;
#   open_file_cache_valid 300s;
    open_file_cache_errors on;

    expires 24h;
    client_max_body_size 20m;
    connection_pool_size 256;
    client_header_buffer_size 1k;
    large_client_header_buffers 4 2k;
    request_pool_size 4k;

    gzip on;
    gzip_min_length 1100;
    gzip_buffers 4 8k;
    gzip_types text/plain;

    output_buffers 1 32k;
    postpone_output 1460;

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;


    ignore_invalid_headers on;
    server_tokens off;

    index index.html index.php;