If plugin `_start` or `_initialize` attempts to invoke any host call, a segmentation fault will occur.

[dev-null-undefined]

Since the ngx_proxy_wasm_instance_t is not yet created and set to the instance->data, every host calls that uses the data field through the ngx_proxy_wasm_instance2pwexec function will cause segmentation fault.

https://github.com/Kong/ngx_wasm_module/blob/main/src/wasm/vm/ngx_wavm.c#L1065