Braintree/src/main/java/com/braintreepayments/api/internal/BraintreeHttpClient.java
public String post(String path, String data) throws Exception {
        if (mAuthorization instanceof ClientToken) {
            data = new JSONObject(data)
                    .put(AUTHORIZATION_FINGERPRINT_KEY, ((ClientToken) mAuthorization).getAuthorizationFingerprint())
                    .toString();
        }
        return super.post(path, data);
    }
public String post(String path, String data) throws Exception {
        if (mAuthorization instanceof ClientToken) {
            data = new JSONObject(data)
                    .put(AUTHORIZATION_FINGERPRINT_KEY, ((ClientToken) mAuthorization).getAuthorizationFingerprint())
                    .toString();
        }
        return super.post(path, data);
    }
Makes a synchronous HTTP POST request to Braintree using the base url, path, and authorization provided.
@see BraintreeHttpClient#post(String, String, HttpResponseCallback)

@param path the path or url to request from the server via HTTP POST
@param data the body of the post request
@return the HTTP response body