[lst-change] Revert "Revert "Implement Cs.CompilationUnit#getWeight()""

This reverts commit 1770ea6.

Author: OlegDokuka

rewrite-csharp/src/main/java/org/openrewrite/csharp/tree/Cs.java

@@ -23,6 +23,9 @@
 import org.openrewrite.csharp.CSharpPrinter;
 import org.openrewrite.csharp.CSharpVisitor;
 import org.openrewrite.java.JavaPrinter;
+import org.openrewrite.java.JavaTypeVisitor;
+import org.openrewrite.java.JavaVisitor;
+import org.openrewrite.java.JavadocVisitor;
 import org.openrewrite.java.internal.TypesInUse;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
@@ -37,6 +40,8 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.UUID;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.singletonList;
@@ -216,6 +221,37 @@ public TypesInUse getTypesInUse() {
             return cache;
         }
 
+        @Transient
+        @Override
+        public long getWeight(Predicate<Object> uniqueIdentity) {
+            AtomicInteger n = new AtomicInteger();
+            new CSharpVisitor<AtomicInteger>() {
+                final JavaTypeVisitor<AtomicInteger> typeVisitor = new JavaTypeVisitor<AtomicInteger>() {
+                    @Override
+                    public JavaType visit(@Nullable JavaType javaType, AtomicInteger n) {
+                        if (javaType != null && uniqueIdentity.test(javaType)) {
+                            n.incrementAndGet();
+                            return super.visit(javaType, n);
+                        }
+                        //noinspection ConstantConditions
+                        return javaType;
+                    }
+                };
+
+                @Override
+                public J preVisit(J tree, AtomicInteger n) {
+                    n.incrementAndGet();
+                    return tree;
+                }
+
+                @Override
+                public JavaType visitType(@Nullable JavaType javaType, AtomicInteger n) {
+                    return typeVisitor.visit(javaType, n);
+                }
+            }.visit(this, n);
+            return n.get();
+        }
+
         @Override
         public Padding getPadding() {
             Padding p;