code: @Deprecated
    @GwtIncompatible
    public static void propagateIfPossible(@NullableDecl Throwable throwable) {
      if (throwable != null) {
        throwIfUnchecked(throwable);
      }
    }
docs: Propagates {@code throwable} exactly as-is, if and only if it is an instance of {@link
  RuntimeException} or {@link Error}. Example usage:
  
  <pre>
  try {
  someMethodThatCouldThrowAnything();
  } catch (IKnowWhatToDoWithThisException e) {
  handle(e);
  } catch (Throwable t) {
  Throwables.propagateIfPossible(t);
  throw new RuntimeException("unexpected", t);
  }
  </pre>
  
  @deprecated Use {@link #throwIfUnchecked}, which has the same behavior but rejects {@code
  null}.