code: public ChronicleMapBuilder<K, V> constantValueSizeBySample(V sampleValue) {
          this.sampleValue = sampleValue;
          averageValue = null;
          averageValueSize = UNDEFINED_DOUBLE_CONFIG;
          return this;
      }
docs: Configures the constant number of bytes, taken by serialized form of values, put into maps,
  created by this builder. This is done by providing the {@code sampleValue}, all values should
  take the same number of bytes in serialized form, as this sample object.
  <p>
  <p>If values are of boxed primitive type or {@link Byteable} subclass, i. e. if value size is
  known statically, it is automatically accounted and this method shouldn't be called.
  <p>
  <p>If value size varies, method {@link #averageValue(Object)} or {@link
  #averageValueSize(double)} should be called instead of this one.
  <p>
  <p>Calling this method clears any previous {@link #averageValue(Object)} and
  {@link #averageValueSize(double)} configurations.
  
  @param sampleValue the sample value
  @return this builder back
  @see #averageValueSize(double)
  @see #averageValue(Object)
  @see #constantKeySizeBySample(Object)