Implemented clientbound packet waypoint 0x8a

libmc-common/src/commonMain/kotlin/cn/rtast/libmc/primitives/Either.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/9/7
+ */
+
+
+package cn.rtast.libmc.primitives
+
+import cn.rtast.libmc.stream.BytesBuffer
+
+public sealed class Either<out L, out R> {
+    public data class Left<out L>(val value: L) : Either<L, Nothing>()
+    public data class Right<out R>(val value: R) : Either<Nothing, R>()
+
+    public val isLeft: Boolean get() = this is Left
+    public val isRight: Boolean get() = this is Right
+}
+
+public suspend inline fun <L, R> BytesBuffer.readEither(
+    readLeft: BytesBuffer.() -> L,
+    readRight: BytesBuffer.() -> R,
+): Either<L, R> {
+    val isLeft = readBoolean()
+    return if (isLeft) Either.Left(readLeft(this)) else Either.Right(readRight(this))
+}
+
+public suspend inline fun <L, R> BytesBuffer.writeEither(
+    either: Either<L, R>,
+    writeLeft: BytesBuffer.(L) -> Unit,
+    writeRight: BytesBuffer.(R) -> Unit,
+) {
+    when (either) {
+        is Either.Left -> {
+            writeBoolean(true)
+            writeLeft(this, either.value)
+        }
+
+        is Either.Right -> {
+            writeBoolean(false)
+            writeRight(this, either.value)
+        }
+    }
+}