Aggregate the data buffers from a body asynchronously.
impl Buf groups the
Bufs from the
copying them. This is ideal if you don’t require a contiguous buffer.
Care needs to be taken if the remote is untrusted. The function doesn’t implement any length
checks and an malicious peer might make it consume arbitrary amounts of memory. Checking the
Content-Length is a possibility, but it is not strictly mandated to be present.