code: def crypto_secretstream_xchacha20poly1305_keygen():
      
      keybuf = ffi.new(
          "unsigned char[]",
          crypto_secretstream_xchacha20poly1305_KEYBYTES,
      )
      lib.crypto_secretstream_xchacha20poly1305_keygen(keybuf)
      return ffi.buffer(keybuf)[:]
docs: Generate a key for use with
      :func:`.crypto_secretstream_xchacha20poly1305_init_push`.