code: public FaunusPipeline transform(final String closure) {
          this.state.assertNotLocked();
          this.state.assertNoProperty();
  
          this.compiler.addMap(TransformMap.Map.class,
                  NullWritable.class,
                  FaunusVertex.class,
                  TransformMap.createConfiguration(this.state.getElementType(), this.validateClosure(closure)));
  
          this.state.lock();
          makeMapReduceString(TransformMap.class);
          return this;
      }
docs: Apply the provided closure to the current element and emit the result.
  
  @param closure the closure to apply to the element
  @return the extended FaunusPipeline