inserting array initialized with zeros violates not-null constraint of schema

In the schema I'm using there is a table called _vectors_ which has a row _vector_.
The row _vector_ has as constraint that it cannot be null.

I have no problems inserting any array into this table except when i try to insert an array initialized with all zeros:
```
Working code:
a := [768]float64{}
a[0] = 1
err := database.Insert(a)

=> Insert OK
```

```
Not working:
a := [768]float64{}
a[0] = 0
err := database.Insert(a)

=> ERROR: null value in column "vector" of relation "vectors" violates not-null constraint (SQLSTATE 23502)
```

Why is this happening? is it a bug of pgx? is it a postgres convention to treat arrays initialized with zeros as null?

Start at the database.Insert call shown in the report and trace how the zero-valued Go array is encoded and sent to PostgreSQL. Reproduce both insertion examples, then determine whether the driver sends a NULL value or an array containing zeros; done means the cause is identified and the all-zero array is handled consistently.

Written by the indexing model from the issue text.