r - Shiny: I don't know how stop one process started by a button by pressing another button -

i need shiny app. i'll try simplify question. problem i'm developing application makes report when button pressed. report takes between 10 , 15 minutes. have button (a 'stop' button) stops previous process doesn't stop application. ilustrate that, i'll show code can take reference resolve app. counting started pressing @ 'count' button, stops if press 'stop' button.

ui.r code:

shinyui(    fluidpage(    actionbutton("count","start count"),    actionbutton("stop","stop count")    ) ) 

server.r code:

shinyserver(function(input, output, session) {     observeevent(input$count, {        observeevent(input$stop, {          # code stop counting       })        <- 1       (i in i:10000) {          print(paste("number: ",i))       }    }) }) 

thanks lot friends!