Function asyncCloseClientOnOutputBufferLimitReached

Asynchronously close a client if soft or hard limit is reached on the * output buffer size. The caller can check if the client will be closed * checking if the client CLIENT_CLOSE_ASAP flag is set. * * Note: we need to close the client asynchronously because this function is * called from contexts where the client can't be freed safely, i.e. from the * lower level functions pushing data insi