1. @DomName('WebGL2RenderingContext.getBufferSubData')
  2. @DocsEditable()
  3. @Experimental()
void getBufferSubData(int target, int offset, ByteBuffer returnedData)

Source 

@DomName('WebGL2RenderingContext.getBufferSubData')
@DocsEditable()
@Experimental() // untriaged
void getBufferSubData(int target, int offset, ByteBuffer returnedData) =>
    _blink.BlinkWebGL2RenderingContext.instance
        .getBufferSubData_Callback_3_(this, target, offset, returnedData);