it is done

core/src/mindustry/world/ItemBuffer.java

@@ -0,0 +1,82 @@
+package mindustry.world;
+
+import arc.util.*;
+import mindustry.type.Item;
+
+import java.io.*;
+
+import static mindustry.Vars.content;
+
+public class ItemBuffer{
+    private final float speed;
+
+    private long[] buffer;
+    private int index;
+
+    public ItemBuffer(int capacity, float speed){
+        this.buffer = new long[capacity];
+        this.speed = speed;
+    }
+
+    public boolean accepts(){
+        return index < buffer.length;
+    }
+
+    public void accept(Item item, short data){
+        //if(!accepts()) return;
+        buffer[index++] = Pack.longInt(Float.floatToIntBits(Time.time()), Pack.shortInt((short)item.id, data));
+    }
+
+    public void accept(Item item){
+        accept(item, (short)-1);
+    }
+
+    public Item poll(){
+        if(index > 0){
+            long l = buffer[0];
+            float time = Float.intBitsToFloat(Pack.leftInt(l));
+
+            if(Time.time() >= time + speed || Time.time() < time){
+                return content.item(Pack.leftShort(Pack.rightInt(l)));
+            }
+        }
+        return null;
+    }
+
+    public short pollData(){
+        if(index > 0){
+            long l = buffer[0];
+            float time = Float.intBitsToFloat(Pack.leftInt(l));
+
+            if(Time.time() >= time + speed || Time.time() < time){
+                return Pack.rightShort(Pack.rightInt(l));
+            }
+        }
+        return -1;
+    }
+
+    public void remove(){
+        System.arraycopy(buffer, 1, buffer, 0, index - 1);
+        index--;
+    }
+
+    public void write(DataOutput stream) throws IOException{
+        stream.writeByte((byte)index);
+        stream.writeByte((byte)buffer.length);
+        for(long l : buffer){
+            stream.writeLong(l);
+        }
+    }
+
+    public void read(DataInput stream) throws IOException{
+        index = stream.readByte();
+        byte length = stream.readByte();
+        for(int i = 0; i < length; i++){
+            long l = stream.readLong();
+            if(i < buffer.length){
+                buffer[i] = l;
+            }
+        }
+        index = Math.min(index, length - 1);
+    }
+}