code: public static boolean equalImplementations(NativeContinuation c1, NativeContinuation c2) {
          return Objects.equals(c1.implementation, c2.implementation);
      }
docs: Returns true if both continuations have equal implementations.
  @param c1 one continuation
  @param c2 another continuation
  @return true if the implementations of both continuations are equal, or they are both null.
  @throws NullPointerException if either continuation is null