More tests

[provinzkraut]

Things that we need tests for:

• File upload
• Parsing of incoming data (Starlite + FastAPI only)
• Handling of request bodies (text/form/json)
• Websockets (More complex, needs a different benchmarking tool)

[Goldziher]

• multipart form data (complex type, dictionary + files, dictionary only, files only, file list etc.)
• url encoded form data.
• reading of cookie parameters
• reading of header parameters