## Problem
Currently, even if `LAMBDA_REMOTE_DOCKER=1`, we unzip the zip files in the directory they are in, which is usually /var/lib/localstack, which usually has a bind mount to the host.
On docker desktop, due to the use of grpc-FUSE (on macos), this can be very slow, about 200 times slower than on volumes / directly on the host. With experimental virtio filesystem enabled (also on macos), this can be reduced to about 30 times as slow, but still problematic.
This means a lambda may take a lot of time processing, for each additional layer some more. This especially affects nodejs lambdas with huge node_modules folders.

## Probable solution
At least if `LAMBDA_REMOTE_DOCKER=1`, we should leave the initial zip files on the bind mount (for persistence etc), but the working directories after unzipping should be located on non-bind mounts, to speed up the IO for unzipping.
"""Get an existing event source mapping
    ---
    operationId: 'getEventSourceMapping'
    parameters:
        - name: 'request'
          in: body
    """
    region = LambdaRegion.get()
    mappings = region.event_source_mappings
    mappings = [m for m in mappings if mapping_uuid == m.get("UUID")]
    if len(mappings) == 0:
        return not_found_error()
    return jsonify(mappings[0])
@app.route("%s/event-source-mappings" % API_PATH_ROOT, methods=["POST"])
def create_event_source_mapping():