int totalBytesRead = 0;
    boolean doneEncoding = endOfInput;

    DRAINING:
    while (true) {
      // We stay in draining mode until there are no bytes left in the output buffer. Then we go
      // back to encoding/flushing.
      if (draining) {
        totalBytesRead += drain(b, off + totalBytesRead, len - totalBytesRead);
        if (totalBytesRead == len || doneFlushing) {