public static void checkState(boolean expression) {
    if (!expression) {
      throw new IllegalStateException();
    }
  }
Ensures the truth of an expression involving the state of the calling instance, but not
involving any parameters to the calling method.

@param expression a boolean expression
@throws IllegalStateException if {@code expression} is false
fbcore/src/main/java/com/facebook/common/internal/Preconditions.java