I'm wondering if this is a bug.

import time
from llama_index.core import Document, VectorStoreIndex
from llama_index.core.schema import TextNode

text = Document.example().text

nodes = [TextNode(text=text)] * 5000

start = time.time()
index = VectorStoreIndex(nodes=nodes)
end = time.time()
print(f"Index creation took {str(end-start)} seconds")

start = time.time()
index.storage_context.persist()
end = time.time()
print(f"Persist took {str(end-start)} seconds")