% cf. http://tools.ietf.org/html/rfc5849#section-3.4.1.1

{base_string, "POST&http%3A%2F%2Fexample.com%2Frequest&a2%3Dr%2520b%26a3%3D2%2520q%26a3%3Da%26b5%3D%253D%25253D%26c%2540%3D%26c2%3D%26oauth_consumer_key%3D9djdj82h48djs9d2%26oauth_nonce%3D7d8f3e4a%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D137131201%26oauth_token%3Dkkk9d7dh3k39sjv7"}.

{method, "POST"}.

{url, "http://example.com/request"}.

{params, [
  {"b5", "=%3D"}
, {"a3", "a"}
, {"c@", ""}
, {"a2", "r b"}
, {"oauth_consumer_key", "9djdj82h48djs9d2"}
, {"oauth_token", "kkk9d7dh3k39sjv7"}
, {"oauth_signature_method", "HMAC-SHA1"}
, {"oauth_timestamp", "137131201"}
, {"oauth_nonce", "7d8f3e4a"}
, {"c2", ""}
, {"a3", "2 q"}
]}.