use separate set of ids

src/commonMain/kotlin/exchange.dydx.abacus/processor/base/MergeWithIds.kt

@@ -8,46 +8,22 @@ fun mergeWithIds(
     existing: List<Any>,
     id: (Any) -> String?,
 ): List<Any> {
-    val merged = mutableSetOf<ItemWithId>()
+    val ids = mutableSetOf<String>()
+    val merged = mutableListOf<Any>()
     new.forEach { item ->
         id(item)?.let { itemId ->
-            merged.add(
-                ItemWithId(
-                    id = itemId,
-                    item = item,
-                ),
-            )
+            ids.add(itemId)
+            merged.add(item)
         }
     }
     existing.forEach { item ->
         id(item)?.let { itemId ->
-            merged.add(
-                ItemWithId(
-                    id = itemId,
-                    item = item,
-                ),
-            )
+            if (!ids.contains(itemId)) {
+                ids.add(itemId)
+                merged.add(item)
+            }
         }
     }
 
-    return merged.map { it.item }
-}
-
-// Wrapper for de-duping in set
-private data class ItemWithId(
-    val id: String,
-    val item: Any,
-) {
-    override fun hashCode(): Int {
-        return id.hashCode()
-    }
-
-    override fun equals(other: Any?): Boolean {
-        if (this === other) return true
-        if (other == null || this::class != other::class) return false
-
-        other as ItemWithId
-
-        return id == other.id
-    }
+    return merged
 }