Save raster files using shinySaveButton - shiny

Question

I would like to read and process a raster file, and after that, I would like to save the result using shinySaveButton
the read and process steps are functioning well, but still, I can not save the output of the process!
library(shiny)
library(raster)
library(rgdal)
library(shinyFiles)
file1<- "D:\\dgm_test.tif"
ui <- fluidPage(
titlePanel(p("Dyke extraction tool", style = "color:#3474A7")),
sidebarLayout(
sidebarPanel(
fileInput(inputId = "dgm", accept = "tif",
label = "Choose a raster"),
actionButton(inputId = "click",
label = "Update"),
shinySaveButton("save", "Save file", "Save file as ...", filetype= ".tif")
# the desired format that I want at the end is .tif
),
mainPanel(
plotOutput("plot1"),
plotOutput("plot2")
)
)
)
server <- function(input, output,session) {
data1<- reactive({
req(input$dgm)
raster::raster(input$dgm$datapath)
})
observeEvent(input$click, {
output$plot1<- renderPlot(
{plot(data1())
}
)
output$plot2<- renderPlot(
{plot(aggregate(data1(), fact=100, fun=mean, expand=TRUE))# I want to enable
the user to save this output as a raster(tif format) ??
}
)
}
)
}
shinyApp(ui = ui, server = server)
could you please assist me to figure out how I can do that?