Name-value pairs giving API parameters. Will be matched into
endpoint
placeholders, sent as query parameters in GET requests, and as a
JSON body of POST requests. If there is only one unnamed parameter, and it
is a raw vector, then it will not be JSON encoded, but sent as raw data, as
is. This can be used for example to add assets to releases. Named NULL
values are silently dropped. For GET requests, named NA
values trigger an
error. For other methods, named NA
values are included in the body of the
request, as JSON null
.