DListView_Column:SetFixedWidth
Example
Creates a DListView and populates it with two columns and two items, only one of which can be selected at a time.
The first column will be longer than the second column.
Output: 
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Sets the fixed width of the column.
Creates a DListView and populates it with two columns and two items, only one of which can be selected at a time.
The first column will be longer than the second column.