Rust SQL x中的mut *transaction和mut transaction有什么区别

我很好奇我的例子中&mut *transaction和&mut transaction之间有什么区别，因为我一开始并不认为transaction是指针，但出于某种原因，&mut *transaction满足trait 约束，而&mut transaction则不满足trait 约束.

这是我的工作代码:

use sqlx::{PgPool, Transaction, Executor};
use chrono::{DateTime, Utc};

pub struct SimpleDbClient {
    db: PgPool,
}

pub trait AddCharacterEntries {
    async fn insert_character_entries(&self, timestamp: DateTime<Utc>, char_values: Vec<(char, i32)>) -> sqlx::Result<()>;
}

impl AddCharacterEntries for SimpleDbClient {
    async fn insert_character_entries(&self, timestamp: DateTime<Utc>, char_values: Vec<(char, i32)>) -> sqlx::Result<()> {
        let mut transaction = self.db.begin().await?;
        for (character, ascii_value) in char_values {
            sqlx::query!(
                r#"
                INSERT INTO character_log (timestamp, character, ascii_value)
                VALUES ($1, $2, $3)
                "#,
                timestamp,
                character as char,
                ascii_value
            )
            .execute(&mut *transaction)
            .await?;
        }
        transaction.commit().await?;
        Ok(())
    }
}

如果我将上面的更改为.execute(&mut transaction)，我会得到这个错误:

rustc: the trait bound `&mut sqlx::Transaction<'_, sqlx::Postgres>: sqlx::Executor<'_>` is not satisfied
the following other types implement trait `sqlx::Executor<'c>`:
  <&'c mut sqlx::PgConnection as sqlx::Executor<'c>>
  <&'c mut sqlx::sqlx_postgres::PgListener as sqlx::Executor<'c>>
  <&'c mut sqlx::AnyConnection as sqlx::Executor<'c>>
  <&sqlx::Pool<DB> as sqlx::Executor<'p>> [E0277]
rustc: required by a bound introduced by this call [E0277]

这归结为进行某种类型的铸造吗？我很好奇这是否会被认为是一种限制，或者编译器认为这两个表达是不同的对象是否真的有意义.