When implementing HTTP/multipart requests and streaming (SSE/chunked) parsing with aiohttp, follow these rules: - Prefer aiohttp’s built-in primitives for multipart bodies (e.g., MultipartWriter) instead of manually encoding file payloads or copying brittle logic from other clients. - Manage ClientResponse lifecycle according to aiohttp connection pooling: don’t call close in a way that breaks pooling; ensure the response is released back to the pool (typically via release/reading/using context managers). - Make streaming parsers robust to transport chunking: never assume chunk boundaries equal line boundaries; split defensively so multiple lines in one chunk and partial lines across chunks are handled. Example patterns: ```python # Multipart: use aiohttp primitive rather than ad-hoc dict encoding writer = aiohttp.MultipartWriter() # ... append parts to writer ... # Response lifecycle: release to pool (avoid breaking pooling semantics) resp = await session.request(...) try: # read/parse as needed ... finally: if not resp.closed: resp.release() # return connection to pool # Streaming parser: be chunk-boundary agnostic async def parse_stream_async(reader): async for chunk in reader: for line in chunk.splitlines(): # handle b"data: " prefix / DONE sentinel as appropriate ... ```