After preparing a request, call
req_stream() to perform the request
and handle the result with a streaming callback. This is useful for
streaming HTTP APIs where potentially the stream never ends.
req_stream(req, callback, timeout_sec = Inf, buffer_kb = 64)
A single argument callback function. It will be called
repeatedly with a raw vector whenever there is at least
worth of data to process. It must return
TRUE to continue streaming.
Number of seconds to processs stream for.
Buffer size, in kilobytes.
An HTTP response.