Add overloaded saveAll method to store collection of entities

[kowalczm]

Allow to store not just streams
Avoid synchronization

[bytefish]

What's the reason for not using the synchronized access for the Collection overload? I am afraid the same PgBulkInsert instance is used by multiple threads, and the concurrent access to the BinaryWriter may cause problems.

[kowalczm]

Generally it is performance reason not to synchronize when not required.
I think it should not be a problem as in saveAll method there is created new instance of PgBinaryWriter for each call. Even if PgBulkInsert could be used by multipe threads but we assume that each thread is using own connection. I think that synchronized was used only for parallel streams?

[bytefish]

You are totally right! It opens its own writer, so it shouldn't be a problem. I will merge your code and release it later today. 🤝