Update one line at time in multiple line chart

Hi Guys,

Thanks for such a great swift chart library.

I am adding multiple line data set in the LineChartView, my question how do i update one line at a time? Because we pass the array of data set in order to draw or update the data of any line. is there any way that I can update one line at a time by getting the value from the chart and update the particular data set?

Start at LineChartView and trace how the array of data sets is accepted for drawing or updating. Determine whether updating one line is a supported capability or requires a defined API change; done should be a decided, documented behavior for updating a particular data set.

Written by the indexing model from the issue text.