annotation_custom in ggplot not supported by plotly

Hi all,
I have a line of code to draw a rectangle, with a gradient color scheme, onto a ggplot figure using annotation_custom. However, this is not supported (and does not appear) when I make my figure interactive with ggplotly.

I am having trouble finding another solution for making this same shape that appears in the static figure in the interactive figure. Is there a way that ggplotly can support custom annotations?
Thank you!

g <- rasterGrob(matrix(c(bluepal), nrow = 1), 
                                 width=unit(1,"npc"), height = unit(1,"npc"), 
                                 interpolate = TRUE) #make a gradient of blue colors 

annotation_custom(g, xmin=2.7, xmax=7.5, ymin=20, ymax=22)
<img width="379" alt="Screen Shot 2021-08-12 at 6 17 45 PM" src="https://user-images.githubusercontent.com/22037535/129281870-c665dea2-0c82-4818-86e2-24d311578342.png">

まず、rasterGrob、annotation_custom、ggplotly を使用して提供された R の例を再現し、静的な ggplot とインタラクティブな結果を比較します。カスタムアノテーションをサポートできるかどうかを判断し、インタラクティブな図にグラデーションの矩形が表示されることを確認します。