bson_writer_rollback man page
bson_writer_rollback — bson_writer_rollback()
void bson_writer_rollback (bson_writer_t *writer);
writer: A bson_writer_t.
Abort the appending of the current bson_t to the memory region managed by writer. This is useful if you detected that you went past a particular memory limit. For example, MongoDB has 48MB message limits.
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