use_oob
if FALSE, use a local webserver for the OAuth dance.
Otherwise, provide a URL to the user and prompt for a validation
code. Defaults to the of the "httr_oob_default"
default,
or TRUE
if httpuv
is not installed.
as_header
If TRUE
, the default, sends oauth in bearer header.
If FALSE
, adds as parameter to url.
cache
A logical value or a string. TRUE
means to cache
using the default cache file .oauth-httr
, FALSE
means
don't cache, and NA
means to guess using some sensible heuristics.
A string mean use the specified p