OpenMetrics support for textfile collector

Currently prometheus_client.exposition.write_to_textfile doesn't support the OpenMetrics text format, which I'm addressing with this (private) hack:

from prometheus_client.openmetrics.exposition import (
    generate_latest as generate_latest_openmetrics,
)
from prometheus_client.registry import CollectorRegistry

def write_openmetrics_to_textfile(path: str, registry: CollectorRegistry) -> None:
    """
    Fork of `prometheus_client.exposition.write_to_textfile`, as the project
    didn't provide an OpenMetrics variant of this helper function.
    """
    with open(path, "wb") as fp:
        fp.write(generate_latest_openmetrics(registry))

Would your project be interested in a non-hacky (as is the case above) OpenMetrics support for textfile collector?

Comienza en prometheus_client.exposition.write_to_textfile y compara su comportamiento con prometheus_client.openmetrics.exposition.generate_latest. Determina cómo debería exponer el helper la salida de OpenMetrics, preservando al mismo tiempo el comportamiento existente del collector de archivos de texto. La tarea estará terminada cuando el helper compatible escriba texto OpenMetrics válido para el registry proporcionado y esté cubierto por las pruebas relevantes del proyecto.