@ExperimentalApi
    public static void setBufferAllocator(SSLEngine engine, BufferAllocator bufferAllocator) {
        toConscrypt(engine).setBufferAllocator(bufferAllocator);
    }
Provides the given engine with the provided bufferAllocator.
@throws IllegalArgumentException if the provided engine is not a Conscrypt engine.
@throws IllegalStateException if the provided engine has already begun its handshake.
common/src/main/java/org/conscrypt/Conscrypt.java