Fix Race (#13)

* reverse iterator init

* some fixes

* fix reverse iterator seaklowerbound

* fix tests

* fix track channels

* longest prefix on txn

* some fixes

* revisit

* todo revisit

* major code refactor

* some minor fixes

* add lru

* fix bugs

* added walk func

* add more tests

* some prog

* some progress track mutate

* some progress

* fix tests

* some optimizations

* some memory optimizations

* fix tests

* minor fixes

* some minor fixes

* some fixes

* fix delete prefix

* some fixes

* init stack

* fix seek lower bound

* clone

* fix watch

* fix clone bug

* some fixes for go mem db

* merge absl

* Fix race

* fix go mod

* fix race in add child

* fix last memdb test

* clone

* fix memdb last tests

* fix race

txn.go

@@ -151,11 +151,12 @@ func (t *Txn[T]) recursiveInsert(node Node[T], key []byte, value T, depth int, o
 			if child != nil {
 				newChildChClone := t.writeNode(child)
 				newChild, val := t.recursiveInsert(newChildChClone, key, value, depth+1, old)
-				node.setChild(idx, newChild)
+				nodeClone := t.writeNode(node)
+				nodeClone.setChild(idx, newChild)
 				if t.trackMutate {
 					t.trackChannel(node.getMutateCh())
 				}
-				return node, val
+				return nodeClone, val
 			}
 
 			// No child, node goes within us
@@ -202,11 +203,12 @@ func (t *Txn[T]) recursiveInsert(node Node[T], key []byte, value T, depth int, o
 		child, idx := t.findChild(node, key[depth])
 		if child != nil {
 			newChild, val := t.recursiveInsert(child, key, value, depth+1, old)
-			node.setChild(idx, newChild)
+			nodeClone := t.writeNode(node)
+			nodeClone.setChild(idx, newChild)
 			if t.trackMutate {
 				t.trackChannel(node.getMutateCh())
 			}
-			return node, val
+			return nodeClone, val
 		}
 	}