1. DomName('WebGL2RenderingContext.copyBufferSubData')
  2. DocsEditable()
  3. Experimental()
void copyBufferSubData(int readTarget, int writeTarget, int readOffset, int writeOffset, int size)

Source 

@DomName('WebGL2RenderingContext.copyBufferSubData')
@DocsEditable()
@Experimental() // untriaged
void copyBufferSubData(int readTarget, int writeTarget, int readOffset, int writeOffset, int size) => _blink.BlinkWebGL2RenderingContext.instance.copyBufferSubData_Callback_5_(this, readTarget, writeTarget, readOffset, writeOffset, size);