community[patch]: Update comments for lazy_load method (#21063)

- [ ] **PR message**: 
- **Description:** Refactored the lazy_load method to use asynchronous
execution for improved performance. The method now initiates scraping of
all URLs simultaneously using asyncio.gather, enhancing data fetching
efficiency. Each Document object is yielded immediately once its content
becomes available, streamlining the entire process.
    - **Issue:** N/A
- **Dependencies:** Requires the asyncio library for handling
asynchronous tasks, which should already be part of standard Python
libraries in Python 3.7 and above.
    - **Email:** [r73327118@gmail.com](mailto:r73327118@gmail.com)

---------

Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/community/langchain_community/document_loaders/chromium.py

@@ -1,6 +1,6 @@
 import asyncio
 import logging
-from typing import Iterator, List
+from typing import AsyncIterator, Iterator, List
 
 from langchain_core.documents import Document
 
@@ -13,14 +13,8 @@ class AsyncChromiumLoader(BaseLoader):
     """Scrape HTML pages from URLs using a
     headless instance of the Chromium."""
 
-    def __init__(
-        self,
-        urls: List[str],
-        *,
-        headless: bool = True,
-    ):
-        """
-        Initialize the loader with a list of URL paths.
+    def __init__(self, urls: List[str], *, headless: bool = True):
+        """Initialize the loader with a list of URL paths.
 
         Args:
             urls: A list of URLs to scrape content from.
@@ -82,3 +76,22 @@ class AsyncChromiumLoader(BaseLoader):
             html_content = asyncio.run(self.ascrape_playwright(url))
             metadata = {"source": url}
             yield Document(page_content=html_content, metadata=metadata)
+
+    async def alazy_load(self) -> AsyncIterator[Document]:
+        """
+        Asynchronously load text content from the provided URLs.
+
+        This method leverages asyncio to initiate the scraping of all provided URLs
+        simultaneously. It improves performance by utilizing concurrent asynchronous
+        requests. Each Document is yielded as soon as its content is available,
+        encapsulating the scraped content.
+
+        Yields:
+            Document: A Document object containing the scraped content, along with its
+            source URL as metadata.
+        """
+        tasks = [self.ascrape_playwright(url) for url in self.urls]
+        results = await asyncio.gather(*tasks)
+        for url, content in zip(self.urls, results):
+            metadata = {"source": url}
+            yield Document(page_content=content, metadata=metadata)