converge on approach that pushes read Result through pipeline

libs/pageserver_api/src/config.rs

@@ -131,14 +131,6 @@ pub struct DiskUsageEvictionTaskConfig {
 pub struct PageServicePipeliningConfig {
     /// Causes runtime errors if larger than max get_vectored batch size.
     pub max_batch_size: NonZeroUsize,
-    pub protocol_pipelining_mode: PageServiceProtocolPipeliningMode,
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
-#[serde(rename_all = "kebab-case")]
-pub enum PageServiceProtocolPipeliningMode {
-    ConcurrentFutures,
-    Tasks,
 }
 
 pub mod statvfs {
@@ -417,7 +409,6 @@ impl Default for ConfigToml {
             no_sync: None,
             page_service_pipelining: Some(PageServicePipeliningConfig {
                 max_batch_size: NonZeroUsize::new(32).unwrap(),
-                protocol_pipelining_mode: PageServiceProtocolPipeliningMode::ConcurrentFutures,
             }),
         }
     }