`Response.getContent()` always returning empty string

[born2snipe]

Version: 7.9.1

Problem

When Response.getContent() is getting called I am always receiving an empty string

Steps to Reproduce

I forked the repo and made a test to expose the problem:

https://github.com/born2snipe/twilio-java/tree/reading-content-always-returning-empty-string

Possible fix

In the Response.getContent() stop checking the available() on the InputStream since it is considered an estimate number of bytes available. Instead, just consume the bytes and store the read bytes into a ByteArrayOutputStream and convert the contents to a String.

[born2snipe]

This appears to be fixed by the changes in: #357