It should still be able to converge. Is this glossy reflection supposed to be weighted agains other behavior, such as diffuse?
The key is to weight it appropriately, which may include a fresnel blend factor. That is what the mi_sample is used for. For example, if the weight is 0.6, then if mi_sample returns less than 0.6 shoot your glossy ray (or rays), otherwise compute your diffuse.
Now, you may also use the mi_sample for choosing a direction for the glossy ray, or altering the normal for computing the reflection, like the way mib_glossy/mia do it. See mib_glossy code for example.
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