Description:
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I would like a way to allow mysqli to connect to an existing socket connection.

My use case:

I have a connection to a remote server over ssh. Using ssh2_tunnel() I can 
create 
a socket stream to the mysql server.

Currently the only way to do this is use the ssh binary to create a listening 
port 
on my local machine and point mysqli to that port. 

I prefer using ssh2 over a direct connection to mysqli because of security 
reasons. This way I can keep mysql server to listen on localhost only. Also I 
would get the added bonus of key-based authentication.

As I already use ssh2 extensively for filesystem changes on the remote machine I 
already have the keys in place to do this.

From what I've understood the mysqlnd extension already uses PHP steams 
internally, so this shouldn't be impossible.