@Override
        public Builder addMixin(Shape shape) {
            if (getId() == null) {
                throw new IllegalStateException("An id must be set before adding a mixin");
            }
            super.addMixin(shape);
            NamedMemberUtils.cleanMixins(shape, members.get());
            return this;
        }
Removes a member by name.

<p>Note that removing a member that was added by a mixin results in
an inconsistent model. It's best to use ModelTransform to ensure
that the model remains consistent when removing members.

@param member Member name to remove.
@return Returns the builder.
smithy-model/src/main/java/software/amazon/smithy/model/shapes/EnumShape.java