Migrate src outside since there is no need to separate api

sources/src/main/java/io/akarin/server/mixin/core/network/NonblockingServerConnection.java

@@ -0,0 +1,12 @@
+package io.akarin.server.mixin.core.network;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.ServerConnection;
+
+@Mixin(value = ServerConnection.class, remap = false)
+public class NonblockingServerConnection {
+    
+}