shadows/framework/src/main/java/org/robolectric/shadows/ShadowCaptureResult.java
public <T> void set(Key<T> key, T value) {
    Preconditions.checkArgument(!resultsKeyToValue.containsKey(key));
    resultsKeyToValue.put(key, value);
  }
public <T> void set(Key<T> key, T value) {
    Preconditions.checkArgument(!resultsKeyToValue.containsKey(key));
    resultsKeyToValue.put(key, value);
  }
Sets the value for a given key.

@throws IllegalArgumentException if there's an existing value for the key.