Tell me about creating overflow buckets in a map when it overflows.

In Go, a map is implemented as a hash table with open addressing and chains for collision resolution. When a bucket (slot) overflows, overflow buckets are created — additional structures where elements that do not fit in the main bucket are placed.

Each bucket contains a fixed number of slots for key-value pairs. If all slots are occupied and a collision occurs, new elements are placed in overflow buckets, which are linked to the main bucket.

This allows efficient storage of a set of elements with minimal collisions, but performance may decrease with a large number of overflow buckets due to the need to traverse chains.

This is roughly how the internal structure of a map is organized, but implementation details may vary between Go versions.