docs: function polylock (params) {
  
  		if (params === undefined)
  			params = {};
  
  		this.queue       = new polylock_ll();
  		this.ex_locks    = {};
  		this.ex_reserved = {};
  		this.sh_locks    = {};
  		this.op_num      = 1;
  
  		this.drain_for_writes = params.write_priority ? true : false;
  
  	}