private final Map<K, V> backingMap;

  /*
   * Per JDK: "the behavior of a map entry is undefined if the backing map has been modified after
   * the entry was returned by the iterator, except through the setValue operation on the map entry"
   * As such, this field must be cleared before every map mutation.
   *
   * Note about volatile: volatile doesn't make it safe to read from a mutable graph in one thread

      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);
      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *

      return delegate;
    }

    @Override
    public V setValue(V value) {
      checkValue(value);
      // Preconditions keep the map and inverse consistent.
      checkState(entrySet().contains(this), "entry no longer in map");
      // similar to putInBothMaps, but set via entry
      if (Objects.equals(value, getValue())) {
        return value;
      }

        setupEpg(_epgMap, et -> ((RoleType) et).getUpdatedTime(), (et, vl) -> ((RoleType) et).setUpdatedTime(DfTypeUtil.toLong(vl)),
                "updatedTime");
        setupEpg(_epgMap, et -> ((RoleType) et).getValue(), (et, vl) -> ((RoleType) et).setValue(DfTypeUtil.toString(vl)), "value");
    }

    @Override
    public PropertyGateway findPropertyGateway(final String prop) {
        return doFindEpg(_epgMap, prop);
    }

      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);
      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *

      this.delegate = checkNotNull(delegate);
    }

    @Override
    protected Entry<K, V> delegate() {
      return delegate;
    }

    @Override
    @ParametricNullness
    public V setValue(@ParametricNullness V value) {
      throw new UnsupportedOperationException();
    }
  }

            .isSameInstanceAs(entry.getValue());
        Object newKey = new Object();
        assertThat(cache.asMap().putIfAbsent(newKey, entry.getValue())).isNull();
        // this getUnchecked() call shouldn't be a cache miss; verified below
        assertThat(cache.getUnchecked(entry.getKey())).isEqualTo(entry.getValue());
        assertThat(cache.getUnchecked(newKey)).isEqualTo(entry.getValue());
        // don't let the new entry get GCed

                return entry;
              }

              @Override
              @ParametricNullness
              public V setValue(@ParametricNullness V newValue) {
                checkArgument(apply(getKey(), newValue));
                return super.setValue(newValue);
              }
            };
          }
        };
      }
    }

    @Override

                return entry;
              }

              @Override
              @ParametricNullness
              public V setValue(@ParametricNullness V newValue) {
                checkArgument(apply(getKey(), newValue));
                return super.setValue(newValue);
              }
            };
          }
        };
      }
    }

    @Override

      for (Entry<K, V> entry : entrySet) {
        assertTrue(map.containsKey(entry.getKey()));
        assertTrue(map.containsValue(entry.getValue()));
        int expectedHash =
            (entry.getKey() == null ? 0 : entry.getKey().hashCode())
                ^ (entry.getValue() == null ? 0 : entry.getValue().hashCode());
        assertEquals(expectedHash, entry.hashCode());
        expectedEntrySetHash += expectedHash;
      }