Doesn't RX doesn't work inside of another C++ class?

[smurthas]

I've been trying to use the ESP8266 to control an iRobot Create 2 (via software serial). I can interact with the Create directly if I import this library into an Arduino sketch and upload to my Adafruit HUZZAH, however if I try to incorporate this code into another C++ class, I can send but not receive. Here is a trivial example:

// SSWrapper.h

#include "SoftwareSerial.h"

#ifndef SSWrapper_h
#define SSWrapper_h

class SSWrapper {
public:

    SSWrapper();

    // just wrap the basics
    void begin();
    void swWrite(uint8_t b);
    int swRead();
    int swAvailable();

private:
    SoftwareSerial softSerial;
};

#endif /* SSWrapper_h */

// SSWrapper.cpp

#include "SSWrapper.h"
#include <inttypes.h>


SSWrapper::SSWrapper() {
}

void SSWrapper::begin() {
    // just hard code in some values, because that's how I had it set up
    softSerial = SoftwareSerial(12, 5, false, 64);
    softSerial.begin(19200);
}

// these are just pass through
void SSWrapper::swWrite(uint8_t b) {
    softSerial.write(b);
}

int SSWrapper::swRead() {
    return softSerial.read();
}

int SSWrapper::swAvailable() {
    return softSerial.available();
}

And finally, an Arduino Sketch:

#include <SSWrapper.h>

SSWrapper ssw;
void setup() {
  ssw.begin();
}

void loop() {
  // now, the other side has sent some bytes to the ESP, so I expect ssw.swAvailable()
  // to be > 1, but it isn't, it's always 0.

  if (ssw.swAvailable() > 0) {
    byte inByte = ssw.swRead();
    Serial.println("some data:");
    Serial.println(int(inByte));
  }
}

I also tried adding some debug code to the interrupt handler readRx function and it doesn't seem to be getting called.