docs: function (layer, operationType) {
  		var duration = this.options.singleAddRemoveBufferDuration,
  		    fn;
  
  		if (duration > 0) {
  			this._singleAddRemoveBuffer.push({
  				type: operationType,
  				layer: layer
  			});
  
  			if (!this._singleAddRemoveBufferTimeout) {
  				fn = L.bind(this._processSingleAddRemoveBuffer, this);
  
  				this._singleAddRemoveBufferTimeout = setTimeout(fn, duration);
  			}
  		} else { // If duration <= 0, process synchronously.
  			this[operationType](layer);
  		}
  	}