newBodyLazy.write(oldBody.substring(endAt, beginAt));
endAt = oldBody.indexOf(FIELD_ACCESS_MARKER_END, beginAt);
if (endAt > -1) {
newBodyLazy.writeLazily(oldBody.substring(beginAt + FIELD_ACCESS_MARKER_BEGIN.length(), endAt));
endAt += FIELD_ACCESS_MARKER_END.length();
} else {
newBodyLazy.write(oldBody.substring(beginAt, beginAt + FIELD_ACCESS_MARKER_BEGIN.length()));