Note that this cannot be a single-thread `mutate` since
we would immediately block forever when trying to send
or receive data.

A multi-thread variant like `concur.blocking_mutate` is
required.

The type of the elements sent through this channel.

Create a lazy list of received values from a channel

This can be used to process all the values of a channel, e.g., you can

sum_channel(ch Channel N : numeric) =>
ch.as_list.sum

Note that in case of several concurrent readers, each value will end up
with being seen by only one reader.

Unless the Channel is closed, this will block to read at least one
value from this Channel.

for debugging

close this Channel

Sending data via `infix <-` will no more be allowed and result in a fault.

Receiving via `prefix <-` or `next` will return `nil` once Channel is closed

dynamic_apply -- apply `f.call` to `Any.this`'s dynamic type and value

This can be used to perform operation on values depending on their dynamic
type.

Here is an example that takes a `Sequence Any` that may contain boxed values
of types `i32` and `f64`. We can now write a feature `get_f64` that extracts
these values converted to `f64` and build a function `sum` that sums them up
as follows:

Get the dynamic type of this instance. For value instances `x`, this is
equal to `type_of x`, but for `x` with a `ref` type `x.dynamic_type` gives
the actual runtime type, while `type_of x` results in the static
compile-time type.

There is no dynamic type of a type instance since this would result in an
endless hierarchy of types. So for Type values, dynamic_type is redefined
to just return Type.type.

send a value to this Channel.

The channel must be open. Sending a value to a closed channel will cause a fault
(pre_fault if `safety` is enabled, otherwise `panic`).

In case the Channel is full, the attempt to send data will block until the Channel
is no longer full or closed.

Has this Channel been closed?

receive the next value from this channel. Return nil if
the channel is empty and closed.

If the channel is open and has no values available, this will
block until values are available or the channel is closed.

NYI: CLEANUP: Since this is a duplicate of `prefix <-`, we could
remove it.

convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.

receive the next value from this channel. Return nil if
the channel is closed.

If the channel is open and has no values available, this will
block until values are available or the channel is closed.

string representation of this type to be used for debugging.

result has the form "Type of '<name>'", but this might change in the future

There is no dynamic type of a type instance since this would result in an
endless hierarchy of types, so dynamic_type is redefined to just return
Type.type here.

Is this type assignable to a type parameter with constraint `T`?

The result of this is a compile-time constant that can be used to specialize
code for a particular type.


it is most useful in conjunction with preconditions or `if` statements as in


or

name of this type, including type parameters, e.g. 'option (list i32)'.

convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.

NYI: Redefinition allows the type feature to be distinguished from its normal counterpart, see #3913

Get a type as a value.

This is a feature with the effect equivalent to Fuzion's `expr.type` call tail.
It is recommended to use `expr.type` and not `expr.type_value`.

`type_value` is here to show how this can be implemented and to illustrate the
difference to `dynamic_type`.