@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof StringFieldValue that)) return false;
        if (!super.equals(o)) return false;
        if (!Objects.equals(spanTrees, that.spanTrees)) return false;
        if (!Objects.equals(value, that.value)) return false;
        return true;
    }
Returns the String value wrapped by this StringFieldValue.

@return the String value wrapped by this StringFieldValue.
document/src/main/java/com/yahoo/document/datatypes/StringFieldValue.java