Describe lobby feature in README, add documentation page with warning

README.md

@@ -40,6 +40,7 @@ https://user-images.githubusercontent.com/856222/141378688-882082be-9efa-4cfe-81
   - Hold: hold clients when server starts, relay when ready, without them noticing
   - Kick: kick clients when server starts, with a starting message
   - Forward: forward client to another IP when server starts
+  - _Lobby: keep client in emulated server with lobby world, teleport to real server when ready ([experimental*](./docs/join-method-lobby.md))_
 - Customizable MOTD and login messages
 - Automatically manages `server.properties` (host, port and RCON settings)
 - Graceful server sleep/shutdown through RCON (with `SIGTERM` fallback on Linux/Unix)

docs/join-method-lobby.md

@@ -0,0 +1,87 @@
+# Join method: lobby
+
+**Note: this is highly experimental, incomplete, and may break your game. See
+[warning](#warning).**
+
+The lobby join method allows you to keep clients in a lobby world while the
+server is starting. When the server is ready, the player is _teleported_ to the
+real server.
+
+`lazymc` emulates a fake server with an empty lobby world. The player is put in
+this world, floating in space. A custom message is shown on the client to notify
+we're waiting on the server to start.
+
+![Lobby screenshot](../res/screenshot/lobby.png)
+
+## Warning
+
+This feature is highly experimental, incomplete and unstable. This may break the
+game and crash clients. Don't use this unless you know what you're doing. Never
+enable this in a production environment.
+
+Current limitations:
+
+- Only works with offline mode
+- Only works with vanilla Minecraft clients, does not work with modded (e.g. Forge, FTB)
+- Probably only works with Minecraft 1.16-1.17.1 (tested with 1.17.1)
+- This method will consume the client, following configured join methods won't be used.
+
+At this time it is unknown if some of the above limitations will ever be lifted,
+or if this will ever be implemented in a robust manner.
+
+## Usage
+
+_Note: you must use `lazymc v0.2.0` or above with the `lobby` feature enabled._
+
+To try this out, simply add the `"lobby"` method to the `join.methods` list in
+your `lazymc.toml` configuration file:
+
+```toml
+# -- snip --
+
+[join]
+methods = [
+    "lobby",
+    "kick",
+]
+
+# -- snip --
+```
+
+Then configure the lobby to your likings:
+
+```toml
+# -- snip --
+
+[join.lobby]
+# Lobby occupation method.
+# The client joins a fake lobby server with an empty world, floating in space.
+# A message is overlayed on screen to notify the server is starting.
+# The client will be teleported to the real server once it is ready.
+# This may keep the client occupied forever if no timeout is set.
+# Consumes client, not allowing other join methods afterwards.
+
+# !!! WARNING !!!
+# This is highly experimental and unstable.
+# This may break the game and crash clients.
+# Don't enable this unless you know what you're doing.
+#
+# - Only works with offline mode
+# - Only works with vanilla Minecraft clients, does not work with modded
+# - Only tested with Minecraft 1.17.1
+
+# Maximum time in seconds in the lobby while the server starts.
+timeout = 600
+
+# Message banner in lobby shown to client.
+message = "§2Server is starting\n§7⌛ Please wait..."
+
+# Sound effect to play when server is ready.
+ready_sound = "block.note_block.chime"
+
+# -- snip --
+
+```
+
+_Note: this might have changed, see the latest configuration
+[here](../res/lazymc.toml)._

res/lazymc.toml

@@ -62,7 +62,7 @@ command = "java -Xmx1G -Xms1G -jar server.jar --nogui"
 [join]
 # Methods to use to occupy a client on join while the server is starting.
 # Read about all methods and configure them below.
-# Methods are used in-order, if none is set, the client disconnects without a message.
+# Methods are used in order, if none is set, the client disconnects without a message.
 #methods = [
 #    "hold",
 #    "kick",
@@ -94,7 +94,7 @@ command = "java -Xmx1G -Xms1G -jar server.jar --nogui"
 # Consumes client, not allowing other join methods afterwards.
 
 # IP and port to forward to.
-# Forwarded-to server will receive original client handshake and login request as received by lazymc.
+# The target server will receive original client handshake and login request as received by lazymc.
 #address = "127.0.0.1:25565"
 
 [join.lobby]
@@ -106,7 +106,7 @@ command = "java -Xmx1G -Xms1G -jar server.jar --nogui"
 # Consumes client, not allowing other join methods afterwards.
 
 # !!! WARNING !!!
-# This is highly experimental and unstable.
+# This is highly experimental, incomplete and unstable.
 # This may break the game and crash clients.
 # Don't enable this unless you know what you're doing.
 #
@@ -114,7 +114,7 @@ command = "java -Xmx1G -Xms1G -jar server.jar --nogui"
 # - Only works with vanilla Minecraft clients, does not work with modded
 # - Only tested with Minecraft 1.17.1
 
-# Maxiumum time in seconds in the lobby while the server starts.
+# Maximum time in seconds in the lobby while the server starts.
 #timeout = 600
 
 # Message banner in lobby shown to client.