bson_sized_new man page
bson_sized_new — bson_sized_new()
bson_t * bson_sized_new (size_t size);
size: The size to pre-allocate for the underlying buffer.
The bson_sized_new() function shall create a new bson_t on the heap with a preallocated buffer. This is useful if you have a good idea of the size of the resulting document.
A newly allocated bson_t that should be freed with bson_destroy().
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