attrData
The data provided to attr.
    Object
  
  import canViewCallbacks from "can-view-callbacks";
import stache from "can-stache";
canViewCallbacks.attr( "my-attr", function( el, attrData ) {
  attrData.scope.peek( "value" ); //-> 123
  attrData.attributeName;       //-> "my-attr"
} );
stache( "<div my-attr='value'/>" )( {
  value: 123
} );