/// <summary>
/// Returns all dataflows targeting specified signal, regardless of their activation times.
/// </summary>
/// <param name="target">signal target to query for</param>
/// <returns>all dataflows targeting specified signal</returns>
public IEnumerable <Flow> GetFlowsTo(SignalRef target)
{
return(_graphs.SelectMany(g => g.GetFlowsTo(target))
.Union(_neutral.GetFlowsTo(target))
.Distinct());
}