@UnstableApi
    public final boolean tryClose() {
        if (setState(State.OPEN, State.CLOSED)) {
            addObjectOrEvent(SUCCESSFUL_CLOSE);
            return true;
        }
        return false;
    }
Tries to close the stream.

@return {@code true} if the stream has been closed by this method call.
        {@code false} if the stream has been closed already by another party.
core/src/main/java/com/linecorp/armeria/common/stream/DefaultStreamMessage.java