@Override
    public int hashCode() {
        int h = hashCode;
        if (h == 0) {
            hashCode = h = Objects.hash(type, qualifiers);
        }
        return h;
    }
Returns true if this type contains the given qualifier.

@param qualifier qualifier to check for.
@return true if this instance contains the given qualifier.
core/src/main/java/org/jdbi/v3/core/qualifier/QualifiedType.java