UnityEngine.GUIStyle.INTERNAL_CALL_SetMouseTooltip C# (CSharp) Method

        private static extern void INTERNAL_CALL_SetMouseTooltip(GUIStyle self, string tooltip, ref Rect screenRect);
        private static void Internal_DrawPrefixLabel(IntPtr style, Rect position, GUIContent content, int controlID, bool on)

 internal void SetMouseTooltip(string tooltip, Rect screenRect)
 {
     GUIStyle.INTERNAL_CALL_SetMouseTooltip(this, tooltip, ref screenRect);
 }