toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
return 'VisibilityMap(level1: $level1, level2: $level2, level3: $level3, level4: $level4, '
'placeholder1: $placeholder1, placeholder2: $placeholder2, placeholder3: $placeholder3)';
}