Describes a failed write command result for a single document.
An integer value identifying the write error.
A document providing more information about the write error (e.g. details pertaining to document validation).
The index of the request that errored.
A description of the error.
https://www.mongodb.com/docs/manual/reference/method/WriteResult/
See Implementation
https://github.com/mongodb/specifications/blob/0b6b96b758259edc91c2fc475bcf08eea54e08e2/source/crud/crud.rst#L1745
Describes a failed write command result for a single document.