[Swift] RealtimeChannelV2: Improve the postgresChange function signature

[LucasAbijmil]

When using RealtimeChannelV2, the filter passed in parameter is a String that must be entered manually by the client.

Let's consider filtering the id (of type UUID) column via an array, our function signature will be as follows:

let changes = channel.postgresChange(
      AnyAction.self,
      table: table,
      filter: “id=in.(\(array.map(\.id.uuidString).joined(separator: ‘,’)))”
)

While this works like a charm, I can see several drawbacks:

• Easy to introduce errors
• Learning curve (especially for PostgREST beginners)
• A syntax far less easy and readable than what we can have for a database query via the functions of PostgrestFilterBuilder.

The idea would be to improve syntax and readability by using something similar to PostgrestFilterBuilder, so that the signature would look something like:

func postgresChange(
    _: InsertAction.Type,
    schema: String = “public”,
    table: String? = nil,
    filter: PostgrestRealtimeFilterBuilder? = nil
  ) -> AsyncStream<InsertAction> 

So, when called (and taking the previous example), we'd have the following:

let changes = channel.postgresChange(
      AnyAction.self,
      table: table,
      filter: .in(“id”, values: array.map(\.id))
)