Added a coroutine dispatcher for server thread

dependencies.gradle

@@ -4,6 +4,7 @@ configurations {
 }
 
 dependencies {
+    compileOnly("com.github.GTNewHorizons:GTNHLib:0.6.36:dev")
     shadowImplementation("org.jetbrains.kotlin:kotlin-stdlib:2.1.10")
     shadowImplementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:2.1.10")
     shadowImplementation("org.jetbrains.kotlin:kotlin-reflect:2.1.10")

src/main/kotlin/net/shadowfacts/forgelin/coroutines/MinecraftServerDispatcher.kt

@@ -0,0 +1,30 @@
+package net.shadowfacts.forgelin.coroutines
+
+import com.gtnewhorizon.gtnhlib.util.ServerThreadUtil
+import cpw.mods.fml.common.Loader
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Runnable
+import kotlin.coroutines.CoroutineContext
+
+internal val isGTNHLibLoaded by lazy { Loader.isModLoaded("gtnhlib") }
+
+/**
+ * The dispatcher that runs the block in the server main thread.
+ *
+ * It's based on the implementation of GTNHLib in [ServerThreadUtil]. Thus GTNHLib is required for this dispatcher.
+ * The coroutine is invoked immediately if the caller is on the server thread; otherwise, it's invoked in the next tick before the pre-tick phase.
+ *
+ * Also be aware that if you dispatch coroutines when the server isn't running, it throws [IllegalStateException].
+ * For the details when the dispatcher is ready, see [ServerThreadUtil].
+ */
+@Suppress("UnusedReceiverParameter", "unused") // use the receiver to prevent polluting the top-level functions
+val Dispatchers.MinecraftServer: CoroutineDispatcher
+    get() = if(isGTNHLibLoaded) MinecraftServerDispatcher
+    else error("GTNHLib is required for Dispatchers.MinecraftServer.")
+
+internal object MinecraftServerDispatcher : CoroutineDispatcher() {
+    override fun dispatch(context: CoroutineContext, block: Runnable) {
+        ServerThreadUtil.addScheduledTask(block)
+    }
+}