🐛 Do NOT rely on autocmd to fix Vim freeze

Close #120

It seems newer Vim supports multiline message from timer so we just
simplify implementation of `helper.echo` by using timer to solve #120.

Author: lambdalisue

denops_std/helper/README.md

@@ -9,13 +9,9 @@
 ### echo / echoerr
 
 Use `echo()` to show messages on the cmdline area. It is required while Vim
-won't show messages reported from channel commands and it won't pause multi-line
-messages reported from asynchronous context (e.g. timer or job). It's same for
+won't show messages reported from channel commands. It's same for
 `denops.cmd('echo "Hello\nWorld!"')` in Neovim.
 
-Note that there is no similar function for `echomsg` while there is no way to
-properly show multi-line messages with `echomsg` from asynchronous context.
-
 ```typescript
 import { Denops } from "https://deno.land/x/denops_std/mod.ts";
 import { echo, echoerr } from "https://deno.land/x/denops_std/helper/mod.ts";
@@ -40,7 +36,7 @@ import { friendlyCall } from "https://deno.land/x/denops_std/helper/mod.ts";
 
 export async function main(denops: Denops): Promise<void> {
   denops.dispatcher = {
-    "say": () => {
+    say: () => {
       return friendlyCall(denops, async () => {
         // Do whatever you want.
         throw new Error("Some error occured");

denops_std/helper/echo.ts

@@ -1,7 +1,5 @@
-import { deferred, Denops } from "../deps.ts";
-import * as anonymous from "../anonymous/mod.ts";
+import { Denops } from "../deps.ts";
 import { batch } from "../batch/mod.ts";
-import { load } from "./load.ts";
 
 /**
  * Echo message as like `echo` on Vim script.
@@ -18,7 +16,10 @@ export function echo(denops: Denops, message: string): Promise<void> {
   if (denops.meta.mode === "test") {
     return Promise.resolve();
   } else if (denops.meta.host === "vim") {
-    return echoVim(denops, message);
+    return denops.cmd(
+      "call timer_start(0, { -> execute('redraw | echo message', '') })",
+      { message },
+    );
   } else {
     return denops.cmd("redraw | echo message", { message });
   }
@@ -61,11 +62,3 @@ export async function friendlyCall(
     }
   }
 }
-
-async function echoVim(denops: Denops, message: string): Promise<void> {
-  await load(denops, new URL("./echo.vim", import.meta.url));
-  const waiter = deferred<void>();
-  const id = anonymous.once(denops, () => waiter.resolve())[0];
-  await denops.call("DenopsStdHelperEcho", message, denops.name, id);
-  await waiter;
-}