@Override
    public void setInitialSupplier(Supplier<BaseStream<?, ?>> initialSupplier) {
        this.initialSupplier = Objects.requireNonNull(initialSupplier);
    }
@author pemi
@param <E> The type element that the last PipelineImpl holds
runtime-parent/runtime-core/src/main/java/com/speedment/runtime/core/internal/stream/builder/pipeline/PipelineImpl.java