Core/src/main/java/com/braintreepayments/api/internal/HttpClient.java
public void post(final String path, final String data, final HttpResponseCallback callback) {
        if (path == null) {
            postCallbackOnMainThread(callback, new IllegalArgumentException("Path cannot be null"));
            return;
        }

        mThreadPool.submit(new Runnable() {
            @Override
            public void run() {
                try {
                    postCallbackOnMainThread(callback, post(path, data));
                } catch (Exception e) {
                    postCallbackOnMainThread(callback, e);
                }
            }
        });
    }
public void post(final String path, final String data, final HttpResponseCallback callback) {
        if (path == null) {
            postCallbackOnMainThread(callback, new IllegalArgumentException("Path cannot be null"));
            return;
        }

        mThreadPool.submit(new Runnable() {
            @Override
            public void run() {
                try {
                    postCallbackOnMainThread(callback, post(path, data));
                } catch (Exception e) {
                    postCallbackOnMainThread(callback, e);
                }
            }
        });
    }
Make a HTTP POST request using the base url and path provided. If the path is a full url,
it will be used instead of the previously provided url.

@param path The path or url to request from the server via HTTP POST
@param data The body of the POST request
@param callback The {@link HttpResponseCallback} to receive the response or error.