Returns the hash code value for this map entry. The hash code
of a map entry {@code e} is defined to be: <pre>
(e.getKey()==null ? 0 : e.getKey().toHash()) ^
(e.getValue()==null ? 0 : e.getValue().toHash())</pre>
This ensures that {@code e1.equals(e2)} implies that
{@code e1.toHash()==e2.toHash()} for any two Entries
{@code e1} and {@code e2}, as required by the general
contract of {@link Object#toHash}.
@return the hash code value for this map entry
@see #equals
Returns the hash code value for this map entry. The hash code of a map entry {@code e} is defined to be: <pre> (e.getKey()==null ? 0 : e.getKey().toHash()) ^ (e.getValue()==null ? 0 : e.getValue().toHash())</pre> This ensures that {@code e1.equals(e2)} implies that {@code e1.toHash()==e2.toHash()} for any two Entries {@code e1} and {@code e2}, as required by the general contract of {@link Object#toHash}.
@return the hash code value for this map entry @see #equals