// we reached EOF
              return new String(buffer, 0, bufIndex);
            }
            // otherwise we got the size wrong.  This can happen if the size changes between when
            // we called sizeIfKnown and when we started reading the file (or I guess if
            // maxCharsPerByte is wrong)
            // Fallback to an incremental approach
            StringBuilder builder = new StringBuilder(bufIndex + 32);