Function create_content_length_stream 

pub fn create_content_length_stream<R>(
    initial_buffer: Vec<u8>,
    reader: R,
    content_length: usize,
    config: &StreamingBodyConfig,
) -> Body
where
    R: AsyncRead + Unpin + Send + Sync + 'static,

Create a streaming body from a Content-Length body.

Returns a fastapi_core::Body::Stream that yields chunks from the given initial buffer and async reader.

Arguments

• initial_buffer - Any bytes already buffered by the parser
• reader - The async reader for remaining bytes
• content_length - Expected total body size
• config - Streaming configuration