Are you familiar with the same-size grow mechanism in maps? What is evacuation in a map and under what operations does it occur?

In Go, a map is designed so that when the number of elements grows, a rehash occurs, redistributing elements into a new structure with more buckets. The same-size grow mechanism is a way to increase the map's capacity without increasing the number of buckets, meaning only the size of each bucket is increased.

Evacuation is the process of moving elements from the old map structure to the new one during its expansion. It occurs during insert operations when the current map is full and needs to increase capacity to maintain performance. During evacuation, elements are gradually copied into the new structure, which helps avoid long pauses.

Thus, evacuation is a key mechanism that enables dynamic scaling of maps in Go, and same-size grow is one of the ways to increase capacity without changing the number of buckets, which can be useful for optimizing element distribution.