Method drain_read_buffer

c/tests/raw_connection_proactor_test.cpp:221–229

  }

  void drain_read_buffer() {
    assert(buff_in_use);
    send(sockfd, "FOO", 3, 0);
    REQUIRE_RUN(p, PN_RAW_CONNECTION_READ);
    pn_raw_buffer_t rb = {0};
    REQUIRE(pn_raw_connection_take_read_buffers(server_rc, &rb, 1) == 1);
    REQUIRE(rb.size == 3);
    buff_in_use = false;
  }

  void give_read_buffer() {
    assert(!buff_in_use);