If the activity was not destroyed then the sleep will be resumed when the activity is resumed. If the activity was destroyed then it will not be resumed.
Example
Sub Activity_Click
Log("cs click")
Sleep(1000)
Log("after")
End Sub
cs click
after
cs click <-- click on the home button
** Activity (main) Pause, UserClosed = false **
sending message to waiting queue (sleep)
running waiting messages (1)
after <-- resumed
** Activity (main) Resume **
cs click
after
cs click <------- click on the back key
** Activity (main) Pause, UserClosed = true **
sending message to waiting queue (sleep)
** Activity (main) Create, isFirst = false **
running waiting messages (1)
Sleep not resumed (context destroyed): anywheresoftware.b4a.shell.DebugResumableSub$RemoteResumableSub <--- not resumed
** Activity (main) Resume **