public static UserLogRingCharBuffer init(
     final InputMethodService context, final boolean enabled, final boolean usabilityStudy) {
   if (!(enabled || usabilityStudy)) {
     return null;
   }
   sUserLogRingCharBuffer.mEnabled = true;
   UsabilityStudyLogUtils.getInstance().init(context);
   return sUserLogRingCharBuffer;
 }
 // TODO: accept code points
 @UsedForTesting
 public void push(final char c, final int x, final int y) {
   if (!mEnabled) {
     return;
   }
   if (LatinImeLogger.sUsabilityStudy) {
     UsabilityStudyLogUtils.getInstance().writeChar(c, x, y);
   }
   mCharBuf[mEnd] = c;
   mXBuf[mEnd] = x;
   mYBuf[mEnd] = y;
   mEnd = normalize(mEnd + 1);
   if (mLength < BUFSIZE) {
     ++mLength;
   }
 }