libs/web: Made luci.http.write a sink

libs/web/luasrc/http.lua

@@ -169,10 +169,17 @@ function status(code, message)
 	coroutine.yield(1, code, message)
 end
 
-function write(content)
-	if not content or #content == 0 then
-		return
+function write(content, src_err)
+	if not content then
+		if src_err then
+			error(src_err)
+		else
+			close()
 		end
+		return true
+	elseif #content == 0 then
+		return true
+	else
 		if not context.eoh then
 			if not context.status then
 				status()
@@ -185,6 +192,8 @@ function write(content)
 			coroutine.yield(3)
 		end
 		coroutine.yield(4, content)
+		return true
+	end
 end
 
 function redirect(url)